fix AbstractLocation warn of config after deployment

- logic was previously wrong, and warned if not already managed
  rather than the other way round.
LocationConfigUtils: improve log message

- if can't read key file, then include in log.warn which file
  we were trying to read.
ssh-keys config: accept ~/ file prefix

- was previously done in CredentialsFromEnv, but that has been deleted
  so we temporarily lost this functionality
Accept unqualified location flags in map, without warning

- if calling locationRegistry.resolve(spec, flags), then flags should
  not be fully qualified. So don't warn about them.
Fix rackspace live tests
Switch to use rackspace-cloudservers-uk instead of cloudservers-uk
Merge pull request #830 from aledsage/fix/various-20130716-1954

Fixes: various things