gbproxy: Check SGSN-orignated BVC RESET if BSS BVC is gone

IF the BSS-BVC is gone gbproxy blocks the BVC towards the SGSN (this is
the only thing it can do since there is no BVC-REMOVE). If the SGSN ever
decides to reset that BVC the gbproxy should not ACK it, but instead
consider the BVCI unknown.

Change-Id: Ic57b39a77adf71abda99ef8af7da1592e2225a0d
Related: SYS#5628, OS#5236
2 files changed