gprs_ns2: drop gprs_ns2_vty, rename vty2 -> vty

Drop the vty(1) code and replace it with vty2. The vty(1) was only
used as intermediate to not develop a vty while developing a new
code base behind. Users of gprs_ns2_ has to use the new vty code.

API change which must be synchronized with osmo-pcu,
osmo-gbproxy, osmo-sgsn.

Change-Id: Ic2059e75d8ede8e5c29c4fef6be608ed79c8a97c
diff --git a/src/gb/Makefile.am b/src/gb/Makefile.am
index 031971b..d0db814 100644
--- a/src/gb/Makefile.am
+++ b/src/gb/Makefile.am
@@ -25,7 +25,7 @@
 		  gprs_bssgp.c gprs_bssgp_util.c gprs_bssgp_vty.c gprs_bssgp_rim.c \
 		  gprs_bssgp_bss.c \
 		  gprs_ns2.c gprs_ns2_udp.c gprs_ns2_frgre.c gprs_ns2_fr.c gprs_ns2_vc_fsm.c gprs_ns2_sns.c \
-		  gprs_ns2_message.c gprs_ns2_vty.c gprs_ns2_vty2.c \
+		  gprs_ns2_message.c gprs_ns2_vty.c \
 		  gprs_bssgp2.c bssgp_bvc_fsm.c \
 		  common_vty.c frame_relay.c