network 93.189.88.0/21 BT IGS route for SILICONTOWER access

AS12541 changed: josemaria.dejulian(at)bt.com 20080527 juan.cerezo(at)bt.com 20091028 descr: BT IGS route for SILICONTOWER access mnt-by: BTIGS-MNT mnt-lower: SILICON-MNT mnt-routes: SILICON-MNT source: RIPE