sequencer: support cleaning up commit messages

The run_git_commit() function already knows how to amend commits, and
with this new option, it can also clean up commit messages (i.e. strip
out commented lines). This is needed to implement rebase -i's 'fixup'
and 'squash' commands as sequencer commands.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: dscho

sequencer.c

@@ -484,7 +484,8 @@ static char **read_author_script(void)
  * author metadata.
  */
 static int run_git_commit(const char *defmsg, struct replay_opts *opts,
-			  int allow_empty, int edit, int amend)
+			  int allow_empty, int edit, int amend,
+			  int cleanup_commit_message)
 {
 	char **env = NULL;
 	struct argv_array array;
@@ -521,9 +522,12 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts,
 		argv_array_push(&array, "-s");
 	if (defmsg)
 		argv_array_pushl(&array, "-F", defmsg, NULL);
+	if (cleanup_commit_message)
+		argv_array_push(&array, "--cleanup=strip");
 	if (edit)
 		argv_array_push(&array, "-e");
-	else if (!opts->signoff && !opts->record_origin &&
+	else if (!cleanup_commit_message &&
+		 !opts->signoff && !opts->record_origin &&
 		 git_config_get_value("commit.cleanup", &value))
 		argv_array_push(&array, "--cleanup=verbatim");
 
@@ -788,7 +792,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
 	}
 	if (!opts->no_commit)
 		res = run_git_commit(opts->edit ? NULL : git_path_merge_msg(),
-				     opts, allow, opts->edit, 0);
+				     opts, allow, opts->edit, 0, 0);
 
 leave:
 	free_message(commit, &msg);