fireball: overlay vzw-specific eri.xml

Remove the default eri.xml and use mcc/mnc-specific overlays. This fixes
the R(oaming) symbol in 3G.

Change-Id: I0c31d7c9a07aefdb9b56056966b3ed0211db916e
fireball: default to Global network mode

Change-Id: I32c97a0dd0e1f8c89f3ba478b1616ceb1a7c6bc0