script: remove obsolete script

script: remove obsolete script

This script's functionality has been incoporated into the redmine-upkeep.py script:

* A backport which is merged is moved to the Resolved state by
  _transform_backport_resolved

* A non-backport issue with all backports resolved/rejected will transition
  from 'Pending Backport' to 'Resolved'.

The only thing not done is changing the "Target Version" which is not
particularly useful anymore as hotfixes frequently invalidate it. Rely on
"Released In" instead.

Signed-off-by: Patrick Donnelly <pdonnell@ibm.com>