locking: wait for locks in `hg cp` and `hg mv`...
locking: wait for locks in `hg cp` and `hg mv`
I traced this back to revision 1822 (64df422), and there's no explanation why we
would prefer to error out instead of waiting for the locks.
Differential Revision:
https://phab.mercurial-scm.org/D8464
