largefiles: use 'dirstate.dirs()' for 'directory pattern' relation check
original implementation queries whether specified pattern is related
or not to largefiles in target context by 'dirstate.__contains__()'.
but this can't recognize 'directory pattern' correctly, so this patch
uses 'dirstate.dirs()' for it.
this patch uses dirstate instead of lfdirstate in 'working' route
(second patch hunk for 'hgext/largefiles/reposetup.py'), because
'dirs()' information may be already built for dirstate but not yet for
lfdirstate at this point. this prevents lfdirstate from building up
and having 'dirs()' information.