Workunit.workunitlist() fails if searching for a workunit in Sasha with a format that includes time suffix

e.g.

> Workunit.WorkunitList('W20140212-110000', 'W20140212-110000', ..

fails to find workunit W20140212-110000.

There's a bug in the way Sasha normalizes the workunit/dfu workunit string, in an attempt to fill in trailing date and time entries to search for low/high range. (A spurious '-' is added)