patchbomb: do not assume the presence of angle brackets around msg-id

RFC 5322 states:
  "Semantically, the angle bracket characters are not part of the
   msg-id; the msg-id is what is contained between the two angle bracket
   characters."

Hence it should be correct to pass a message Id with no angle brackets
to --in-reply-to. Adding them if missing.

hgext/patchbomb.py

@@ -397,6 +397,13 b' def patchbomb(ui, repo, *revs, **opts):'
     ui.write('\n')
 
     parent = opts.get('in_reply_to') or None
+    # angle brackets may be omitted, they're not semantically part of the msg-id
+    if parent is not None:
+        if not parent.startswith('<'):
+            parent = '<' + parent
+        if not parent.endswith('>'):
+            parent += '>'
+
     first = True
 
     sender_addr = email.Utils.parseaddr(sender)[1]