Fix serveral bugs all having to do with freeing an
sctp_inpcb:
- Make sure not to remove the flag on the PCB until after the close() caller is back in control with the lock. Otherwise a quickly freeing assoc could kill the inpcb and cause a panic.
- Make sure all calls to log_closing have not released the locks before calling the log function, we don't want the logging function to crash us due to a freed inpcb.
- Make sure that when we get to the end, we release all locks (after removing them from view) and as long as we are NOT the inp-kill timer removing the inp, call the callout_drain() function so a racing timer won't later call in and cause a racing crash.
MFC after: 1 week