Block I/O while SG reset operation in progress

Following the discussion with Mike Anderson on the original patch:
http://marc.theaimsgroup.com/?l=linux-scsi&m=114081263725777&w=2
and
http://marc.theaimsgroup.com/?l=linux-scsi&m=114080001928462&w=2
http://marc.theaimsgroup.com/?l=linux-scsi&m=114080001916527&w=2
http://marc.theaimsgroup.com/?l=linux-scsi&m=114080002012180&w=2

I've implemented the missing item of waking up those waiting for recovery to complete as well as restarting queues that may have been stopped.

In conversations with Mike, it's agreed that this patch is sufficient to block i/o while performing resets via SG - the original immediate goal. However, we've noted several other issues in this interface that will need to be addressed eventually.

-- james s