votequorum: Fix auto_tie_breaker behaviour in odd-sized clusters

auto_tie_breaker can behave incorrectly in the case of a cluster
with an odd number of nodes. It's possible for a partition to
have quorum while the other side has the ATB node, and both will
continue working. (Of course in a properly configured cluster one side
will be fenced but that becomes an indeterminate race .. just what ATB
is supposed to avoid).

This patch prevents ATB from running in a partition if the 'other'
partition might have quorum, and also mandates the use of wait_for_all
in clusters with an odd number of nodes so that a quorate partition
cannot start services or fence an existing partition with the tie
breaker node.

Signed-Off-By: Christine Caulfield <ccaulfie@redhat.com>
Reviewed-by: Jan Friesse <jfriesse@redhat.com>