Fix buck build

Bring up to date with latest version gerrit.  It was failing with
following messages:

* TypeError: java_test() got an unexpected keyword argument 'source_under_test'
* No build file at lib/jgit/BUCK when resolving target //lib/jgit:jgit

Change-Id: Ic6372e1275c11aaf9a513cb161e1ba3e17a9a35b

BUCK

diff --git a/BUCK b/BUCK
index f0df7a4..f0e4181 100644
--- a/BUCK
+++ b/BUCK
@@ -1,3 +1,5 @@
+include_defs('//bucklets/gerrit_plugin.bucklet')
+
 gerrit_plugin(
   name = 'its-phabricator',
   srcs = glob(['src/main/java/**/*.java']),
@@ -53,16 +55,13 @@
   name = 'its-phabricator_tests',
   srcs = glob(['src/test/java/**/*.java']),
   labels = ['its-phabricator'],
-  source_under_test = [':its-phabricator__plugin'],
-  deps = [
+  deps = GERRIT_PLUGIN_API + GERRIT_TESTS + [
     ':its-phabricator__plugin',
     '//plugins/its-base:its-base_tests-utils',
     ':its-base_stripped',
-    '//gerrit-plugin-api:lib',
     '//lib/easymock:easymock',
     '//lib:guava',
     '//lib/guice:guice',
-    '//lib/jgit:jgit',
     '//lib:junit',
     '//lib/log:api',
     '//lib/log:impl_log4j',