[OCSgw] Make sure Graceful shutdown works correctly

[mpeterss]

It seems like the P-GW sometimes keeps on sending CCR-U for new buckets. Although we reply with with Final-Unit-Indication terminate. The RFC is not telling me how to handle this so we need to hunt down a pcap or find some more doc on how this is supposed to work.

[mpeterss]

I changed some settings on the P-GW to abort-terminate and not retry. Lets see if this makes any difference.