mslookup_client.c: fix dereferencing null pointer

Fixes: CID#207547
Change-Id: If19e1e68fad76a3d65788ac208da7dde1f8745c1
diff --git a/src/mslookup/mslookup_client.c b/src/mslookup/mslookup_client.c
index 67977e4..ce46296 100644
--- a/src/mslookup/mslookup_client.c
+++ b/src/mslookup/mslookup_client.c
@@ -146,7 +146,7 @@
 	if (!req) {
 		LOGP(DMSLOOKUP, LOGL_ERROR,
 		     "Internal error: Got mslookup result for a request that does not exist (handle %u)\n",
-		     req->request_handle);
+		     request_handle);
 		return;
 	}