mutex: remove nlock assertions
mutex: remove nlock assertions

These do not work when we cond.Wait(lock), because the lock drop via the
Cond wait does not decrement nlock.  Just remove them, they're obvious
anyway.

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph