Only reconnect if the endpoint wasn't freed.

peer_abort() should only attempt to reconnect if the endpoint wasn't
freed.  Also remove hwtid from the debugfs idr.

Add missing check for peer2peer in MPAv2 code

Use correct mpa version on reject.
Signed-off-by: Vipul Pandya <vipul@chelsio.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>