When in direct mode, update the master branch after committing to the
annex/direct/master branch. Also, update the synced/master branch.
This fixes a topology A->B where both A and B are in direct mode and
running the assistant, and a change is made to B. Before this fix, A pulled
the changes from B, but since they were only on the annex/direct/master
branch, it did not merge them.
Note that I considered making the assistant merge the
remotes/B/annex/direct/master, but decided to keep it simple and only merge
the sync branches as before.
