commit: clear resolved mergestate even if working copy is clean If the mergestate has resolved conflicts and a commit is successfully created (either because there are changes in the working copy or because ui.allowemptycommit=yes), we will also clear the merge state. However, if the working copy is clean (and ui.allowemptycommit=no), we leave the mergestate there. The user may notice it in `hg resolve -l` output (but not in `hg status -v` output). It's not clear how the user should clear it, but probably via `hg co -C .`. It's also quite likely that they won't even notice it and it will get cleared by a later `hg commit` (of unrelated changes). This patch makes it so that `hg commit` also clears resolved merge conflicts even if the command doesn't end up writing a commit because the working copy was empty. That's probably a little weird (commands that abort should generally avoid changing the repo), but it still seems mostly harmless, and it reduces the risk of more bugs like https://bz.mercurial-scm.org/show_bug.cgi?id=5494. I just ran into a version of that bug in the Evolve extension and that's what triggered this series. Differential Revision: https://phab.mercurial-scm.org/D8196