Buck: Adjust to upstream change: "default java targeted to be Java 7"

60efceb upstream change flips the default version of java targeted to be
Java 7 rather than the EoL'd Java 6.  Now we don't need to overwrite
Buck's own python methods to enforce Java 7 to be the default Java version.

Moreover, projects that want to switch to newer Java version (e. g. Java 8)
can do it now in .buckconfig file:

  [java]
    source_level = 8
    target_level = 8

[1] https://github.com/facebook/buck/commit/60efceb5239134d709be4087916e95e07542519a

Change-Id: I3e22b798e18b013a5b43922cb0fdf601f76921a7
diff --git a/java7.bucklet b/java7.bucklet
deleted file mode 100644
index 1c65359..0000000
--- a/java7.bucklet
+++ /dev/null
@@ -1,87 +0,0 @@
-# Copyright (C) 2013 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-# Current Buck version lacks support to overwrite Java version
-# in .buckconfig file, under Java section, e. g.:
-#
-# [java]
-#   src_roots = java, resources
-#   source = 7
-#   target = 7
-#
-# Instead, the documentaion suggests to provide Java version in
-# each and every java_library() call.
-#
-# This bucklet overwrites the definition of original java_library
-# and java_test rules.
-#
-# Example: this bucklet must be used in .buckconfig file, under
-# include section to ensure, that this file is seen before others:
-#
-# [buildfile]
-#   includes = //bucklets/java7.bucklet
-#
-# @See https://github.com/facebook/buck/pull/67
-#
-original_java_library = java_library
-def java_library(
-    name,
-    srcs=[],
-    resources=[],
-    source='7',
-    target='7',
-    proguard_config=None,
-    deps=[],
-    exported_deps=[],
-    visibility=[],
-    ):
-  original_java_library(
-    name=name,
-    srcs=srcs,
-    resources=resources,
-    source=source,
-    target=target,
-    proguard_config=proguard_config,
-    deps=deps,
-    exported_deps=exported_deps,
-    visibility=visibility,
-  )
-
-original_java_test = java_test
-def java_test(
-    name,
-    srcs=[],
-    labels=[],
-    resources=[],
-    source='7',
-    target='7',
-    vm_args=[],
-    source_under_test=[],
-    contacts=[],
-    deps=[],
-    visibility=[],
-    ):
-  original_java_test(
-    name=name,
-    srcs=srcs,
-    labels=labels,
-    resources=resources,
-    source=source,
-    target=target,
-    vm_args=vm_args,
-    source_under_test=source_under_test,
-    contacts=contacts,
-    deps=deps,
-    visibility=visibility,
-  )
diff --git a/java8.bucklet b/java8.bucklet
deleted file mode 100644
index 96e2514..0000000
--- a/java8.bucklet
+++ /dev/null
@@ -1,87 +0,0 @@
-# Copyright (C) 2013 The Android Open Source Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-# Current Buck version lacks support to overwrite Java version
-# in .buckconfig file, under Java section, e. g.:
-#
-# [java]
-#   src_roots = java, resources
-#   source = 8
-#   target = 8
-#
-# Instead, the documentaion suggests to provide Java version in
-# each and every java_library() call.
-#
-# This bucklet overwrites the definition of original java_library
-# and java_test rules.
-#
-# Example: this bucklet must be used in .buckconfig file, under
-# include section to ensure, that this file is seen before others:
-#
-# [buildfile]
-#   includes = //bucklets/java8.bucklet
-#
-# @See https://github.com/facebook/buck/pull/67
-#
-original_java_library = java_library
-def java_library(
-    name,
-    srcs=[],
-    resources=[],
-    source='8',
-    target='8',
-    proguard_config=None,
-    deps=[],
-    exported_deps=[],
-    visibility=[],
-    ):
-  original_java_library(
-    name=name,
-    srcs=srcs,
-    resources=resources,
-    source=source,
-    target=target,
-    proguard_config=proguard_config,
-    deps=deps,
-    exported_deps=exported_deps,
-    visibility=visibility,
-  )
-
-original_java_test = java_test
-def java_test(
-    name,
-    srcs=[],
-    labels=[],
-    resources=[],
-    source='8',
-    target='8',
-    vm_args=[],
-    source_under_test=[],
-    contacts=[],
-    deps=[],
-    visibility=[],
-    ):
-  original_java_test(
-    name=name,
-    srcs=srcs,
-    labels=labels,
-    resources=resources,
-    source=source,
-    target=target,
-    vm_args=vm_args,
-    source_under_test=source_under_test,
-    contacts=contacts,
-    deps=deps,
-    visibility=visibility,
-  )