[SCSI] hpsa: fix incorrect abort diagnostic message

In the abort handler, when asked to abort a command which
is not known to the driver, SUCCESS is returned, but the
diagnostic message incorrectly indicates the abort failed.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>