Merge branch 'stable-2.16'

* stable-2.16:
  Include Project indexer lib into the plugins API

Change-Id: Ifeea8f59d93d4603dff691a9f504ed04b52c0f86

plugins/BUILD

@@ -33,6 +33,7 @@ EXPORTS = [
     "//java/com/google/gerrit/extensions:api",
     "//java/com/google/gerrit/git",
     "//java/com/google/gerrit/index",
+    "//java/com/google/gerrit/index/project",
     "//java/com/google/gerrit/index:query_exception",
     "//java/com/google/gerrit/json",
     "//java/com/google/gerrit/lifecycle",