Make sure we're pushing to existing master branch

qa/qa/specs/features/merge_request/rebase_spec.rb

@@ -20,6 +20,8 @@ module QA
         push.project = project
         push.file_name = "other.txt"
         push.file_content = "New file added!"
+        push.branch_name = "master"
+        push.new_branch = false
       end
 
       merge_request.visit!