MFC r196260.

MFC r196260.
 * Fix a bug where PR-SCTP settings are ignore when using implicit
   association setup.
 * Fix a bug where message with illegal stream ids are not deleted.
 * Fix a crash when reporting back unsent messages from the send_queue.
 * Fix a bug related to INIT retransmission when the socket is already
   closed.
 * Fix a bug where associations were stalled when partial delivery API
   was enabled.
 * Fix a bug where the receive buffer size was smaller than the
   partial_delivery_point.

Approved by: re, rrs (mentor)

git-svn-id: svn://svn.freebsd.org/base/stable/8@196261 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f