fsmonitor: use configitem
We might as well get this out of the way.
Differential Revision: https://phab.mercurial-scm.org/D893
fsmonitor: access copymap in new location
fsmonitor has been busted since
0865d25e8a8a due to moving
self._copymap. Fix it.
Differential Revision: https://phab.mercurial-scm.org/D892