Set correct object_kind on tag push data.

app/services/create_tag_service.rb

@@ -40,7 +40,9 @@ class CreateTagService < BaseService
   end
 
   def create_push_data(project, user, tag)
-    Gitlab::PushDataBuilder.
+    data = Gitlab::PushDataBuilder.
       build(project, user, Gitlab::Git::BLANK_SHA, tag.target, 'refs/tags/' + tag.name, [])
+    data[:object_kind] = "tag_push"
+    data
   end
 end

app/services/git_tag_push_service.rb

@@ -16,7 +16,8 @@ class GitTagPushService
   private
 
   def create_push_data(oldrev, newrev, ref)
-    Gitlab::PushDataBuilder.
-      build(project, user, oldrev, newrev, ref, [])
+    data = Gitlab::PushDataBuilder.build(project, user, oldrev, newrev, ref, [])
+    data[:object_kind] = "tag_push"
+    data
   end
 end