mq: fix queue.apply to not call os.chdir()
call to os.chdir broke "hg -R dirname qpush".
instead pass -d (change directory) option to patch command.
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
adding b