Adding python-memcache to pkgs

The patch adds python-memcache to pkg list. Barbican api
dependency on python-memcache therefore the pks is going
to be added and insatlled during barbican.server state.

Change-Id: Ic189b2d85a9bb0c04fc14489cae561776684203c
Related-PROD: PROD-21338 (PROD:21338)
1 file changed