update openstack-common.conf and import from oslo
Import add'l files from Nova

Import lots of files from Nova at rev
f0da3464ab17552f24977d22365fa9573702f5a8
Rename files and fix things.
un-split the db backend
Fix failing db and deploy_helper tests

- minor cleanup of db/sqlalchemy/api
- fix some things in conf_fixtures
- fix tests in deploy_helper
- remote unused retry_on_deadlock method
- remove network and service from test.py
move common things to ironic.common

Move from ironic/ to ironic/common/
 config.py
 context.py
 exception.py
 paths.py
 policy.py
 safe_utils.py
 states.py
 utils.py
merge and trim utils and test_utils

Merge baremetal/utils and nova utils
Merge baremetal/test_utils and nova/test_utils
Remove many unused methods from both files
Update test_pxe for merged utils.py
Fix IPMI tests
Initial draft of a Pecan-based API