IB/ipath: Use S_ABORT not cancel and abort on exit freeze mode after recovery

This centralizes the use of the abort functionality, removes the
unneeded buffer cancel (abort does the same thing), sets up to ignore
launch errors after abort, same as cancel.  We need abort on exit from
freeze mode to avoid having buffers stuck in the busy state, if a user
process happened to complete the send while we were in freeze mode
doing the recovery.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>