Update buck to the latest version

This version includes a lot of new features and improvements,
including:

* Switched to top-down-building, which should generally make builds
  faster. The old behavior can be bypassed by passing --deep on the
  command line [1]

* New query command was added (inspired by Bazel) [2]

* Performance improvement in file globbing

Extend tools/eclipse/project.py to pass the --deep option to ask Buck
to execute bottom-up build when generating the Eclipse project. This is
needed otherwise after using the buck clean command only the gerrit.war
file would be fetched from the cache and the buck-out/gen/lib folder
would remain empty.

With [3] genrule output is now namespaced with the genrule name. Adapt
documentation and references in the code to the new location of Buck
artifacts. Because of this change, `buck clean` must be issued after
Buck upgrade, otherwise the build would fail. The same prolem exists
when switching between branches: `buck clean` must be issued, otherwise
the build would fail.

Test plan:

* buck build release
* buck build api_install
* buck test
* install and verify new gerrit site
* upgrade and verify existing gerrit site
* reindex existing gerrit site
* verify that tools/eclipse/project.py produces sane Eclipse project
* verify that unit test execution from Eclipse works
* verify that daemon started from Eclipse works
* verify that GWT SDM debug session started from Eclipe works

[1] https://github.com/facebook/buck/commit/217cec33bcd0b0eb7ebd0c444938495379267d60
[2] https://buckbuild.com/command/query.html
[3] https://github.com/facebook/buck/commit/c92ef212b53fff08a8452649b4d4faadc6b89b11

Change-Id: Ib3f22e70b7cb9eb9349618f2bcc018bf799c40f8
diff --git a/Documentation/dev-buck.txt b/Documentation/dev-buck.txt
index 49a4d85..36a6d06 100644
--- a/Documentation/dev-buck.txt
+++ b/Documentation/dev-buck.txt
@@ -106,7 +106,7 @@
 The output executable WAR will be placed in:
 
 ----
-  buck-out/gen/gerrit.war
+  buck-out/gen/gerrit/gerrit.war
 ----
 
 
@@ -121,7 +121,7 @@
 The output executable WAR will be placed in:
 
 ----
-  buck-out/gen/headless.war
+  buck-out/gen/headless/headless.war
 ----
 
 === Extension and Plugin API JAR Files
@@ -137,8 +137,8 @@
 
 ----
   buck-out/gen/gerrit-plugin-api/plugin-api.jar
+  buck-out/gen/gerrit-plugin-api/plugin-api-javadoc/plugin-api-javadoc.jar
   buck-out/gen/gerrit-plugin-api/plugin-api-src.jar
-  buck-out/gen/gerrit-plugin-api/plugin-api-javadoc.jar
 ----
 
 Install {extension,plugin,gwt}-api to the local maven repository:
@@ -170,7 +170,7 @@
 The JAR files will also be packaged in:
 
 ----
-  buck-out/gen/plugins/core.zip
+  buck-out/gen/plugins/core/core.zip
 ----
 
 To build a specific plugin:
@@ -224,7 +224,7 @@
 The html files will also be bundled into `searchfree.zip` in this location:
 
 ----
-  buck-out/gen/Documentation/searchfree.zip
+  buck-out/gen/Documentation/searchfree/searchfree.zip
 ----
 
 To build the executable WAR with the documentation included:
@@ -236,7 +236,7 @@
 The WAR file will be placed in:
 
 ----
-  buck-out/gen/withdocs.war
+  buck-out/gen/withdocs/withdocs.war
 ----
 
 [[soyc]]
@@ -272,7 +272,7 @@
 The output release WAR will be placed in:
 
 ----
-  buck-out/gen/release.war
+  buck-out/gen/release/release.war
 ----
 
 [[all]]