Logging improvements

- bind_log decorator to bind kwargs to log
- CannotExecutePolicyError logged as msg: TBD fully
all rest methods kwargs changed to undersore names

to have logs consistent with rest of the system
Also, having bind_log but using it internally in with_transaction_id
reverted ignoring CannotExecutePolicyError change
reverting ignore exception changes
pep8 fix
incomplete - started tests
added test to check if bind_log from with_trans_id works
Merge branch 'master' into better_logs
changed test to reflect bind changes
Merge pull request #330 from rackerlabs/better_logs

AUTO-494: All REST arguments logged by default