Enable nova Verbose logging

With oslo-incubator commit 751c35b1c8ff0730883a8ccdda9b77a49fff2405,
(Change-Id: Ic9e3cb5979b2d7283552ad3a461870373f45a239)
Verbose does not enable debug level logging.

Change-Id: I1741ec0ca61e4c7234ee4e29cbd52ded73995451
Merge "Enable nova Verbose logging"
Support Tempest config file format transition

* Identity server location just configure by an URI
* Image service location resolved by service endpoint
* Credentials will be defined only in the identity section
* Whitebox gets it's own section
* ssh username is per image option

Change-Id: I3b0d51a323560451c5636363896cadb39e0ea2d6
Merge "Support Tempest config file format transition"
lib/quantum: refactor quantum plugins and third party

As quantum plugin support is coming like floodlight, nvp and nec,
it's worth while to refactor quantum plugin logic so that each plugin can
be modified/enhanced intervening with other quantum plugin.
And new plugin support can be added easily (hopefully) without modifying
core logic.

Change-Id: Ic5ab5b993272fdd3b4e779823323777a845ee681