Call Bupstash once for each item to delete.

By calling Bupstash once for each item to delete we avoid having to
pipe in a list of IDs through stdin.  Piping ID lists in through stdin
has proven unreliable, keeping Bupstash waiting for the end of file
marker indefinitely in some cases.

Change-Id: Id9a2a9f9e88260882a7de08554d667f02db54673
1 file changed