The roads I take...

As Justin Wood (Callek) just checked in the move of DOM inspector to its own hg repo, your next pull of comm-central will probably error out in client.py because it needs to pull the removal of inspector from mozilla-central before it tries to add the new dom-inspector repo in the place of the previous code.
Another run of client.py should fix this again and you can pull as before.

Thanks to Justin for taking over the completion of this task!