mergestate: don't pop stateextras when there are no conflicts on filemerge Even if `filemerge.filemerge()` didn't result in conflicts, we should not remove stateextras for a file since we now use that for more things than just merge time information. We use stateextras to store information which is required to be used by commit. I tracked this down while finding why a patch of mine which adds more commit related information does not work as expected and looses the extras in mergestate. Differential Revision: https://phab.mercurial-scm.org/D10148