Reflected video elements hit assertion on Lion
https://bugs.webkit.org/show_bug.cgi?id=112490

Disable the new reflected video functionality added in r145915
on Lion because of a nasty re-entrancy problem. Tracked by bug 112490.

* platform/graphics/ca/mac/PlatformCALayerMac.mm:
(PlatformCALayer::clone):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145983 268f45cc-cd09-0410-ab3c-d52691b4dbfc