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'

Change-Id: I7f25ad81b8ae53ab41f477f84835cb801d5ef439
diff --git a/BUCK b/BUCK
index b7e4802..d0b3fd8 100644
--- a/BUCK
+++ b/BUCK
@@ -1,3 +1,5 @@
+include_defs('//bucklets/gerrit_plugin.bucklet')
+
 gerrit_plugin(
   name = 'its-rtc',
   srcs = glob(['src/main/java/**/*.java']),
@@ -58,10 +60,8 @@
   name = 'its-rtc_tests',
   srcs = glob(['src/test/java/**/*.java']),
   labels = ['its-rtc'],
-  source_under_test = [':its-rtc__plugin'],
-  deps = [
+  deps = GERRIT_PLUGIN_API + GERRIT_TESTS + [
     ':its-rtc__plugin',
-    '//gerrit-plugin-api:lib',
     '//lib:junit',
     '//plugins/its-rtc/lib:mockito',
   ],