sanlock: WAIT flag for sanlock_inq_lockspace
    
    New SANLK_INQ_WAIT for sanlock_inq_lockspace().
    
    When the SANLK_INQ_WAIT flag is used the command will block and wait for
    the ongoing procedure (add_lockspace/rem_lockspace) to complete before
    returning the status.
    
    sanlock_inq_lockspace() still returns:
    
    0               lockspace exists and is not being added or removed
    -EINPROGRESS    add or rem is in progress, when the flag SANLK_INQ_WAIT
                    is not used
    -ENOENT         no lockspace with matching name and disk location is
                    found
    
    Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>