• Consolidate the code that free's chunks to actually also call the sctp_free_remote_address() function.
• Assure that when we allocate a chunk the whoTo is NULL, also when we free it and place it into the cache we NULL it (that way the consolidation code will always work).
• Fix a small race, when a empty data holder is left on the stream out queue, and both sides do a shutdown, the empty data holder would prevent us from sending a SHUTDOWN-ACK and at the same time we never would cleanup the empty holder (since nothing was ever in queue). We now add a utility function that a) cleans up empty holders and b) properly determines if there are still pending data chunks on the stream out wheel.

Approved by: re@freebsd.org (Ken Smith)