Expand the comment explaining the workaround for the Snow Leopard

Expand the comment explaining the workaround for the Snow Leopard
timeout bug.

Make the code for the workaround assume any 10.6.x release other than
10.6.2 requires it; that way we don't have to update the code until
either

	1) Apple fixes the bug in a later 10.6.x update

or

	2) Apple comes out with a major release that still has, or
	   reintroduces, the bug.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@32349 f5534014-38df-0310-8fa8-9805f1628bb7