more lock logging

Logging 'released lock' message only when lock was acquired. Not when it
fails to get intermittently. Also logging different claim ids when not
able to acquire lock
updated tests
lint fix
setting seconds variables to None instead of 0 - thanks @cyli

This is to avoid unnecessary dependency of advancing the clock while
writing tests
Merge pull request #33 from rackerlabs/lock_diff_claim_log

more lock logging