gsm0408: Provide unique strings for the gsm 04.08 message

At Rhizomatica we see that some GSM 04.08 messages are leaked and
have no other indication if that is Call Control, SMS or something
else.
diff --git a/openbsc/src/osmo-bsc/osmo_bsc_bssap.c b/openbsc/src/osmo-bsc/osmo_bsc_bssap.c
index 2d2507e..a60940d 100644
--- a/openbsc/src/osmo-bsc/osmo_bsc_bssap.c
+++ b/openbsc/src/osmo-bsc/osmo_bsc_bssap.c
@@ -473,7 +473,7 @@
 	LOGP(DMSC, LOGL_INFO, "Rx MSC DTAP, SAPI: %u CHAN: %u\n", header->link_id & 0x07, header->link_id & 0xC0);
 
 	/* forward the data */
-	gsm48 = gsm48_msgb_alloc();
+	gsm48 = gsm48_msgb_alloc_name("GSM 04.08 DTAP RCV");
 	if (!gsm48) {
 		LOGP(DMSC, LOGL_ERROR, "Allocation of the message failed.\n");
 		return -1;