lock: Fix import cycle breakage

fa2049f caused an import cycle between lock.py and misc.py.  Move the
needed functions from lock.py to lockstatus.py so that we can avoid the
import cycle.

Signed-off-by: Sam Lang <sam.lang@inktank.com>
Merge pull request #10 from ceph/wip-fix-importcycle

lock: Fix import cycle breakage

Reviewed-by: Warren Usui <warren.usui@inktank.com>