ns2: Fix memory leak in IP-SNS

Don't allocate msg twice - it's not nice.

Change-Id: I3fa0076eb480a7bcadb74cc86760dc29b77ac600
Related: OS#4874
diff --git a/src/gb/gprs_ns2_message.c b/src/gb/gprs_ns2_message.c
index eb9a198..6c7f08f 100644
--- a/src/gb/gprs_ns2_message.c
+++ b/src/gb/gprs_ns2_message.c
@@ -498,7 +498,7 @@
 			const struct gprs_ns_ie_ip6_elem *ip6_elems,
 			unsigned int num_ip6_elems)
 {
-	struct msgb *msg = gprs_ns2_msgb_alloc();
+	struct msgb *msg;
 	struct gprs_ns_hdr *nsh;
 	uint16_t nsei;
 
@@ -652,7 +652,7 @@
 int ns2_tx_sns_size(struct gprs_ns2_vc *nsvc, bool reset_flag, uint16_t max_nr_nsvc,
 			 int ip4_ep_nr, int ip6_ep_nr)
 {
-	struct msgb *msg = gprs_ns2_msgb_alloc();
+	struct msgb *msg;
 	struct gprs_ns_hdr *nsh;
 	uint16_t nsei;