Fix gppkg error: 'SyncPackages' object has no attribute 'ret'.

The command `gppkg --clean` fails with the following error: "'SyncPackages' object has no attribute 'ret'".

This occurs because `operations` was being passed positionally during the OperationWorkerPool initialization, which incorrectly bound it to the `should_stop` argument instead of `items` in the base WorkerPool class.

The solution is to  pass `operations` as a keyword argument..

Author: woblerr

gpMgmt/bin/gppylib/commands/base.py

@@ -230,7 +230,7 @@ def __init__(self, numWorkers=16, operations=None):
         if operations is not None:
             for operation in operations:
                 self._spoof_operation(operation)
-        super(OperationWorkerPool, self).__init__(numWorkers, operations)
+        super(OperationWorkerPool, self).__init__(numWorkers, items=operations)
 
     def check_results(self):
         raise NotImplementedError("OperationWorkerPool has no means of verifying success.")