Merge branch 'pw/rebase-skip-final-fix'

Checking out all the paths from HEAD during the last conflicted
step in "git rebase" and continuing would cause the step to be
skipped (which is expected), but leaves MERGE_MSG file behind in
$GIT_DIR and confuses the next "git commit", which has been
corrected.

* pw/rebase-skip-final-fix:
  rebase --continue: remove .git/MERGE_MSG
  rebase --apply: restore some tests
  t3403: fix commit authorship

sequencer.c

@@ -4716,6 +4716,9 @@ static int commit_staged_changes(struct repository *r,
 		    refs_delete_ref(get_main_ref_store(r), "",
 				    "CHERRY_PICK_HEAD", NULL, 0))
 			return error(_("could not remove CHERRY_PICK_HEAD"));
+		if (unlink(git_path_merge_msg(r)) && errno != ENOENT)
+			return error_errno(_("could not remove '%s'"),
+					   git_path_merge_msg(r));
 		if (!final_fixup)
 			return 0;
 	}