flowworker: simplify pseudo packet use

Pseudo packets originating in the flow worker do not need to leave the
flow worker. Putting those in the ThreadVars::decode_pq will make them
be evaluated by the next steps in the pipeline, but those will all
ignore pseudo packets.

Instead, this patch returns them to the packet pool, while still honoring
the IPS verdict logic.

(cherry picked from commit 3247e39)

src/flow-worker.c

@@ -395,12 +395,13 @@ static inline void FlowWorkerStreamTCPUpdate(ThreadVars *tv, FlowWorkerThreadDat
         /* no need to keep a flow ref beyond this point */
         FlowDeReference(&x->flow);
 
+        /* no further work to do for this pseudo packet, so we can return
+         * it to the pool immediately. */
         if (timeout) {
             PacketPoolReturnPacket(x);
         } else {
-            /* put these packets in the preq queue so that they are
-             * by the other thread modules before packet 'p'. */
-            PacketEnqueueNoLock(&tv->decode_pq, x);
+            /* to support IPS verdict logic, in the non-timeout case we need to do a bit more */
+            TmqhOutputPacketpool(tv, x);
         }
     }
 }