Regression from 9f0026001bfd. That previous commit is not supposed
to affect log calls without --follow, so we step out of this
codepath if follow is not True, and it's enough to fix the
regression.
When --follow is given, we fix the issue by taking into account
changesets that have a rev > maxrev to build the filegraph: even if
those files are not included in the final result, it's still needed
to walk correctly the graph from the end of the filelog to minrev, to
track accurately renames.
Without specifying the parent revision of the working copy, users will
update to tip, which is most likely the other head they were trying to
merge, not the revision they were at before the merge.
