gprs_ns2: vty: fix removing a bind from a SNS

Return 0 after removing a bind. Otherwise the vty would return a
wrong error to the user.

Change-Id: I088c18abafc82ae7bd7b8c487ad9e9b448c42ba9
diff --git a/src/gb/gprs_ns2_vty.c b/src/gb/gprs_ns2_vty.c
index a782c5c..2777641 100644
--- a/src/gb/gprs_ns2_vty.c
+++ b/src/gb/gprs_ns2_vty.c
@@ -217,6 +217,7 @@
 		if (vnse_bind->vbind == vbind) {
 			llist_del(&vnse_bind->list);
 			talloc_free(vnse_bind);
+			return 0;
 		}
 	}