Don't translate log messages.
1011257: Throw Conflict exception on StaleStateException

Wrap stale edits in a custom ConcurrentModificationException so that a
clients recieve a 409 with a more descriptive message.
Merge pull request #400 from candlepin/alikins/untranslate_log_messages

Don't translate log messages.
Merge pull request #401 from candlepin/mstead/better-msg-on-stale-edit

1011257: Throw Conflict exception on StaleStateException
Merge remote-tracking branch 'origin/master' into dgoodwin/logging