Since OSP14 has containerized UC, the current way of checking
for config file in /etc will fail and ths even though
config-parser is configured to look at /var/lib/config-data
the task would be skipped.
Using ansible_env.HOME to source stackrc.
Change-Id: I72d7d8572cdbac9b5fb3e8c8b5366b9f77dc03ec