gfs2-utils: Fix hang on withdraw
    
    Issuing a withdraw on a gfs2 filesystem causes a hang. When
    gfs_controld was removed, the userspace functionality that
    completes a withdraw operation went away. This causes gfs2
    kernel to hang waiting for a withdraw completion ack from
    userspace.
    
    This patchset introduces a uevent-based shell script to do
    the job that gfs_controld used to do on withdraw. An 'offline'
    uevent triggers the execution of this script. This script
    suspends the device associated with the filesystem and signals
    a completed withdraw to the kernel.
    
    Resolves: rhbz#1225634
    Signed-off-by: Abhi Das <adas@redhat.com>