Allow region_name_for_services to be configured.

Only when the region_name_for_services can be configured to the heat
region name, heat can support multiple region scenarion when creating
the stack.

Change-Id: I386a81f4ee616bc46357aa9f2cc42b78c47108f1
Closes-Bug: #1330319
use new python_packages attributes from -common

*_python_packages attributes are being moved to -common in order to
remove the duplication from all the cookbooks which are using them

Change-Id: Ia0d26ef915dc27b8654d1ed0dec63b2ecef05743
Implements: blueprint move-python-db-client-attrs-to-common