Remove copyright from empty files

According to policy change in HACKING:
http://docs.openstack.org/developer/hacking/#openstack-licensing
empty files should no longer contain copyright notices.

This patch aslo changes files in ironic/openstack/common, which
were changed in oslo https://review.openstack.org/#/c/64082/

Change-Id: I85fdbc2d94200b6e47ad7c9b8717d4578de2eaee
Closes-Bug: #1262424
Improve the node driver interfaces validation output

This patch improves the output of the node driver interfaces validation
to return the reason why the interface failed to validate.

The new structure looks like:

{'deploy':  {'result': True},
 'power':   {'result': False, 'reason': 'Invalid IPMI username'},
 'console': {'result': None, 'reason': 'not supported'},
 'rescue':  {'result': None, 'reason': 'not supported'}}

The patch also remove an unneeded log that was logging the errors for
each interface, every time the validation was called.

Change-Id: Id5d8aa1bd150b7d85f359471daccfacb6d9e2ede
Closes-Bug: #1263210
Correct SSHPowerDriver validate() exceptions

Driver valdiate() method should raise only InvalidParameterValue
exceptions, which will be caught by
ConductorManager.validate_driver_interfaces().

The SSH driver was potentially raising a FileNotFound exception which
would be unhandled. This patch converts that into InvalidParamterValue.

Change-Id: I82d9776206c1391ba151614ac7512865f8ea672c
Merge "Improve the node driver interfaces validation output"
Merge "Correct SSHPowerDriver validate() exceptions"
Merge "Remove copyright from empty files"