mounts: mark Ashran reput mounts as unobtainable (#139)
mounts: mark Ashran reput mounts as unobtainable (#139)

Also remove their "faction" attribute since they are usable by both
Alliance and Horde and both add to the total mount count.

Fixes #99
kevinclement/SimpleArmory,kevinclement/SimpleArmory,kevinclement/SimpleArmory