alua: Do not add preferred path priority for active/optimized

alua: Do not add preferred path priority for active/optimized

When a path is in active/optimized we should disregard the
'preferred path' bit when calculating the priority.
Otherwise we'll end up with having two different priorities
(one for 'active/optimized (preferred)' and one for
'active/optimized (non-preferred)').
Which will result in two different path groups and a
sub-optimal path usage.

Signed-off-by: Hannes Reinecke <hare@suse.de>