GFS2 mount fails incorrectly after correctly failed second-mount attempt
    
    When a user attempts to mount a GFS2 file system to a second mount
    point, gfs_controld was not properly storing the id of the second
    mount point in its mount point information.  If the mount attempt
    fails, (for example, due to mount options incompatible with the
    original mount), the mount point information was not being deleted
    properly because of the missing id.  That caused subsequent mount
    attempts to fail.  This patch stores the ID in the mount point
    information so that it can be found later and removed properly for
    failed mounts.
    
    rhbz#559735