PutAssignee: Don't gather results of adding assignee as reviewer

This populates the account info in the AddReviewerResult, but
PutAssignee is not using this result.

Change-Id: I1a6caa0e95d1cac21cc28c2fbd9db638aac8bfbf
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-server/src/main/java/com/google/gerrit/server/change/PutAssignee.java

@@ -70,7 +70,6 @@ public class PutAssignee implements
       bu.addOp(rsrc.getId(), reviewersAddition.op);
 
       bu.execute();
-      reviewersAddition.gatherResults();
       return Response.ok(AccountJson.toAccountInfo(op.getNewAssignee()));
     }
   }