Updating commit does not happen when creating or changing branch

[jdemeyer]

When you push to an existing branch on a ticket, you get a message like

Branch pushed to git repo; I updated commit sha1. New commits:
<list of commits>

However, this does not happen when setting the initial branch name or changing branches. I think that setting/changing a branch should be treated the same way as pushing to an existing branch.

[slel]

For reference, discussion of this issue on the sage-devel mailing list:

• [sage-devel] Trac sometimes delays displaying commits until next comment
  https://groups.google.com/d/topic/sage-devel/E8z8qW4O-oc/discussion

[embray]

I'm sure it's fixable but it's hardly a priority for me.