revlog: resolve lfs rawtext to vanilla rawtext before applying delta
This happens when a LFS delta base gets a non-LFS delta from another client.
In that case, the LFS delta base needs to be converted to non-LFS version
before applying the delta.
Differential Revision: https://phab.mercurial-scm.org/D2069
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ hg init
$ echo 'base' > base
$ hg ci -Ambase
adding base
$ hg qnew -mmqbase mqbase
$ hg qsave
$ hg qrestore 2
restoring status: hg patches saved state