wt-status: don't show divergence advice when committing

wt-status: don't show divergence advice when committing

When the user is in the middle of making a commit, they are not yet at
the point where they are ready to think about integrating their local
branch with the corresponding remote branch or force-pushing over the
remote branch. Don't include advice on how to deal with divergent
branches in the commit template, to avoid giving the impression that the
divergence needs to be dealt with immediately. Similar advice will be
printed when it is most relevant, that is, if the user does try to push
without first reconciling the two branches.

Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>