Discovery return_entire_cache does not work.

Please Check https://github.com/belaban/JGroups/blob/master/src/org/jgroups/protocols/Discovery.java#L301

This line was changed in JGRP-2098.

Previous code was below. This worked fine.
sendDiscoveryResponse(addr, physical_addr, NameCache.get(addr), msg.getSrc(), isCoord(addr));

Current code is below.
sendDiscoveryResponse(addr, physical_addr, NameCache.get(addr), msg.getSrc(), is_coord);

If this node is a coordinator, this change will cause all PingData responses to be recognized as Coord and return_entire_cache will not work properly.