rhg: Accept different "invalid ignore pattern" error message formatting
At the moment rhg compiles all patterns into a single big regular expression,
so it’s not practical to find out which file the invalid bit of syntax
came from.
Differential Revision: https://phab.mercurial-scm.org/D11942
$ 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