Bugfix for Global Workqueue

When splitting a large dataset (>100 blocks) the workqueue can blow up and leave
the requests in funny states. This comes from the latest additions triggering
the max size of an URI in an update call to couch.
Merge pull request #4439 from dballesteros7/fixWorkQueue

Bugfix for Global Workqueue
0.9.45

Signed-off-by: Stephen Foulkes <sfoulkes@fnal.gov>