Add pre-release PyPI jobs for WSME

WSME releases beta versions before doing official
releases to allow non-OpenStack projects to test
updates or avoid packages that aren't fully baked.
This change adds the jobs to publish to PyPI when
pre-release tags are added to the repository.

Change-Id: I65ca7e58f60597aecf63748c5788f6a8a83eac2e
Merge "Add pre-release PyPI jobs for WSME"