Use tarball for python-reddwarfclient dependency

* Openstack-ci creates a tarball at tarballs.o.o when tag matches:
  ref: ^refs/tags/([0-9]+\.)+[0-9]*
        (alpha|beta|candidate|rc|a|b|c|r|g)[0-9]*$

Fixes bug#1131509

Change-Id: I5e3d00c57dfe977f6e9a01dea25b97c8fcdf0d1d
Merge "Use tarball for python-reddwarfclient dependency"