Buck: Move //bucklets.defs import to .buckconfig

I767f582f8 added facility to import bucklets but included it in every
buck file.  This is what buildfile section in .buckconfig is for.

Change-Id: I2e7c34684779470514218da1a9332f6386934eda
diff --git a/.buckconfig b/.buckconfig
index f143d0e..01c79be 100644
--- a/.buckconfig
+++ b/.buckconfig
@@ -5,6 +5,9 @@
   mvn_install = //:install
   mvn_deploy = //:deploy
 
+[buildfile]
+  includes = //bucklets.defs
+
 [java]
   src_roots = java, resources
 
diff --git a/BUCK b/BUCK
index dc197fa..329fc6d 100644
--- a/BUCK
+++ b/BUCK
@@ -1,5 +1,4 @@
 include_defs('//VERSION')
-include_defs('//bucklets.defs')
 include_bucklets(['maven_package.bucklet'])
 
 DEPS = [
diff --git a/gitiles-servlet/BUCK b/gitiles-servlet/BUCK
index dcbeaea..df2f629 100644
--- a/gitiles-servlet/BUCK
+++ b/gitiles-servlet/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets([
   'java_sources.bucklet',
   'java_doc.bucklet',
diff --git a/gitiles-war/BUCK b/gitiles-war/BUCK
index 37708a5..f51e211 100644
--- a/gitiles-war/BUCK
+++ b/gitiles-war/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['war.bucklet'])
 
 war(
diff --git a/lib/BUCK b/lib/BUCK
index bdaaf61..8f398c0 100644
--- a/lib/BUCK
+++ b/lib/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['maven_jar.bucklet'])
 
 maven_jar(
diff --git a/lib/guice/BUCK b/lib/guice/BUCK
index 59a4655..7f4c4ef 100644
--- a/lib/guice/BUCK
+++ b/lib/guice/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['maven_jar.bucklet'])
 
 VERSION = '4.0-beta'
diff --git a/lib/jetty/BUCK b/lib/jetty/BUCK
index c007231..e1043de 100644
--- a/lib/jetty/BUCK
+++ b/lib/jetty/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['maven_jar.bucklet'])
 
 VERS = '8.1.7.v20120910'
diff --git a/lib/jgit/BUCK b/lib/jgit/BUCK
index 9e7225c..828bbeb 100644
--- a/lib/jgit/BUCK
+++ b/lib/jgit/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['maven_jar.bucklet'])
 
 REPO = GERRIT
diff --git a/lib/slf4j/BUCK b/lib/slf4j/BUCK
index 410061f..4c99d52 100644
--- a/lib/slf4j/BUCK
+++ b/lib/slf4j/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['maven_jar.bucklet'])
 
 VERS = '1.6.1'
diff --git a/lib/soy/BUCK b/lib/soy/BUCK
index 050239d..9cef651 100644
--- a/lib/soy/BUCK
+++ b/lib/soy/BUCK
@@ -1,4 +1,3 @@
-include_defs('//bucklets.defs')
 include_bucklets(['maven_jar.bucklet'])
 
 maven_jar(