lock: move acquirefn call to inside the lock We're going to need to call it again as part of reinitialization after a subprocess inherits the lock.

localrepo: call lock.lock with releasefn as a keyword arg We'll be adding an acquirefn argument soon, and this makes that clearer.

copies: move debug statement to appropriate place

bidmerge: choose shortest list of diverge and rename/delete warnings Slightly less arbitrary than choosing the first set.