Various logging fixes

Log transaction allocation errors as such. While at it, use proper
subsystem to log missing VLR subscriber.

Change-Id: I617be8793b9416ccd49022c72f7d93df7f4fb4d9
diff --git a/src/libmsc/gsm_09_11.c b/src/libmsc/gsm_09_11.c
index 12bec9d..608d4ff 100644
--- a/src/libmsc/gsm_09_11.c
+++ b/src/libmsc/gsm_09_11.c
@@ -101,7 +101,7 @@
 		trans = trans_alloc(conn->network, conn->vsub,
 				    GSM48_PDISC_NC_SS, tid, new_callref++);
 		if (!trans) {
-			DEBUGP(DMM, " -> No memory for trans\n");
+			LOGP(DMM, LOGL_ERROR, " -> No memory for trans\n");
 			gsm48_tx_simple(conn,
 				GSM48_PDISC_NC_SS | (tid << 4),
 				GSM0480_MTYPE_RELEASE_COMPLETE);
@@ -298,7 +298,7 @@
 	trans = trans_alloc(net, vsub, GSM48_PDISC_NC_SS,
 		0xff, gsup_msg->session_id);
 	if (!trans) {
-		DEBUGP(DMM, " -> No memory for trans\n");
+		LOGP(DMM, LOGL_ERROR, " -> No memory for trans\n");
 		return NULL;
 	}