message: Fix a similar issue of commit when occurs conflict on uses merge --squash.
diff: @@ -592,6 +592,7 @@ Commit Repository::commit(
  // Cleanup merge state.
  switch (state()) {
  + case GIT_REPOSITORY_STATE_NONE:
  case GIT_REPOSITORY_STATE_MERGE:
  case GIT_REPOSITORY_STATE_REVERT:
  case GIT_REPOSITORY_STATE_CHERRYPICK:
  