Init command was not working properly as it could not locate the
configuration sample file.
Steps taken:
- Move config-generator.tempest.conf to etc so it will be installed
with pbr.
- Update all files with new path to config-generator-tempest.conf as
needed.
- Refactor init command so if it detects we are not in a virtual
environment, try to find the global config directory /etc/tempest.
If that fails fallback to [sys.prefix]/etc/tempest.
Closes-Bug: #1491058
Closes-Bug: #1490670
Change-Id: I960bc711ff78ac2b0441ef63dff8ec4fb268fd3a
0bf52d497b