gfs-kernel and mount.gfs2: GFS ignore the noatime and nodiratime mount options
    
    Since the vfs moved the MS_NOATIME, MS_NODIRATIME flags
    from the superblock to the vfsmount structure (MNT_NOATIME,
    MNT_NODIRATIME, which are not accessible to gfs), gfs no
    longer knows when to enable/disable atime updates and the
    atime_quantum stuff is broken in the sense that it doesn't
    respect the noatime and nodiratime flags.
    
    This patch attempts to fix this by creating a gfs-specific
    mount option gfs_noatime and having the mount.gfs helper
    pass it along when the user specifies noatime or nodiratime
    in the command line. It's not the ideal way to fix it, and
    it is a bit ugly.