[SGSN] Gb Proxy: Simplify configuration

Almost all parameters about the SGSNs NS-VC can be specified in the NS
protocol node.  All that needs to remain in the gbproxy config node
is "nsip sgsn nsei XXX".
diff --git a/openbsc/src/gprs/osmo_gbproxy.cfg b/openbsc/src/gprs/osmo_gbproxy.cfg
index d51b04a..29dbe93 100644
--- a/openbsc/src/gprs/osmo_gbproxy.cfg
+++ b/openbsc/src/gprs/osmo_gbproxy.cfg
@@ -6,8 +6,10 @@
  no login
 !
 gbproxy
-  nsip bss local port 23000
-  nsip sgsn remote ip 127.0.0.1
-  nsip sgsn remote port 7777
-  nsip sgsn nsei 101
-  nsip sgsn nsvci 101
+ nsip bss local port 23000
+ nsip sgsn nsei 101
+ns
+ nse 101 nsvci 101
+ nse 101 remote-ip 192.168.100.239
+ nse 101 remote-port 7777
+ nse 101 remote-role sgsn