threads: include name in error message

When a thread fails to spawn, include the thread name in the error
message.

src/tm-threads.c

@@ -1683,7 +1683,7 @@ TmEcode TmThreadSpawn(ThreadVars *tv)
 
     int rc = pthread_create(&tv->t, &attr, tv->tm_func, (void *)tv);
     if (rc) {
-        FatalError("Unable to create thread with pthread_create(): retval %d: %s", rc,
+        FatalError("Unable to create thread %s with pthread_create(): retval %d: %s", tv->name, rc,
                 strerror(errno));
     }