return_entire_cache can prevent group from forming

I have managed to get my group into a position such that a dead member with a 'low' logical address is in the logical address cache, and as a result no-one is able to form a view.

All members loop round at ClientGmsImpl.java line 130-ish, going:

• The group contains only clients
• I'm not the 'first' client (the dead member is)
• So I'll wait for someone else to become coordinator

Because return_entire_cache is true, everyone continues to discover the dead element and continues to wait for him to become coordinator.

I think there needs to be some way for the dead member's address to be marked as removable in the logical address cache, and to expire.