votequorum: Add extended options to auto_tie_breaker

This patch adds more flexibility to the auto_tie_breaker feature of
votequorum. With this, not only can the lowest nodeid be used as
a tie breaker, but also the highest, or a node from a nominated list.

If there is a list of nodes, the first node in the list that was not
part of the previous partition is used. This allows the user to
specify a preferred set of nodes but prevents a split-brain if the
cluster divides evenly with a node in each half.

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