Provide a label for the test suite

Having a separate label that matches the plugin's repository name
allows easier inclusion in CI systems.

Change-Id: I3af35a39078513a7458efd7fe5c417f4f2dcafb6
diff --git a/BUCK b/BUCK
index 2e8a623..8a84334 100644
--- a/BUCK
+++ b/BUCK
@@ -18,6 +18,7 @@
 java_test(
   name = 'replication_tests',
   srcs = glob(['src/test/java/**/*.java']),
+  labels = ['replication'],
   deps = [
     ':replication__plugin',
     '//gerrit-common:server',