patman: Allow specifying the message ID your series is in reply to

Some versions of git don't seem to prompt you for the message ID that
your series is in reply to.  Allow specifying this from the command
line.

Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/tools/patman/patman.py b/tools/patman/patman.py
index e049081..377408d 100755
--- a/tools/patman/patman.py
+++ b/tools/patman/patman.py
@@ -53,6 +53,8 @@
 parser.add_option('-p', '--project', default=project.DetectProject(),
                   help="Project name; affects default option values and "
                   "aliases [default: %default]")
+parser.add_option('-r', '--in-reply-to', type='string', action='store',
+                  help="Message ID that this series is in reply to")
 parser.add_option('-s', '--start', dest='start', type='int',
        default=0, help='Commit to start creating patches from (0 = HEAD)')
 parser.add_option('-t', '--test', action='store_true', dest='test',
@@ -163,7 +165,7 @@
     cmd = ''
     if ok or options.ignore_errors:
         cmd = gitutil.EmailPatches(series, cover_fname, args,
-                options.dry_run, cc_file)
+                options.dry_run, cc_file, in_reply_to=options.in_reply_to)
 
     # For a dry run, just show our actions as a sanity check
     if options.dry_run: