sanlock: configurable mlockall level
    
    -l 0 -> no mlockall
    -l 1 -> mlockall(CURRENT)
    -l 2 -> mlockall(CURRENT|FUTURE)
    
    The default is now set to 1 (was 2).
    
    CURRENT|FUTURE results in each pthread_create using
    8MB of RSS for the thread stack.  CURRENT alone does
    not.
    
    Signed-off-by: David Teigland <teigland@redhat.com>