Remove docutils pin

This was added to work around bug 1091333.  A new sphinx has been
released and so this is no longer necessary.

Change-Id: I174c5aff18b4432277399310154acaeb55c2ed5c
Depends-On: I6ea61a3cc441dd1ca2ced7e2fd837a55b917f76d
Merge "Remove docutils pin"