Update Buck

java_library() now accepts provided_deps argument which replaces
our custom use of java_library2().

This change replaces compile_deps with provided_deps parameter in
gerrit_{plugin,extension} rules. Plugins that are using it must be
updated.

Change-Id: I16d53793da567c958267f91ca203e9cae6c4d02f

gerrit-war/BUCK

diff --git a/gerrit-war/BUCK b/gerrit-war/BUCK
index a96d095..7e11aea 100644
--- a/gerrit-war/BUCK
+++ b/gerrit-war/BUCK
@@ -1,6 +1,6 @@
 include_defs('//tools/git.defs')
 
-java_library2(
+java_library(
   name = 'init',
   srcs = glob(['src/main/java/**/*.java']),
   deps = [
@@ -23,7 +23,7 @@
     '//lib/log:api',
     '//lib/jgit:jgit',
   ],
-  compile_deps = ['//lib:servlet-api-3_1'],
+  provided_deps = ['//lib:servlet-api-3_1'],
   visibility = [
     '//:',
     '//gerrit-gwtdebug:gwtdebug',