notify anyone waiting in packetqueue before waiting on a packet in motion detection. Should fix decode lockup

src/zm_monitor.cpp

@@ -1846,6 +1846,7 @@ bool Monitor::Analyse() {
           while (!snap->decoded and !zm_terminate and !analysis_thread->Stopped()) {
             // Need to wait for the decoder thread.
             Debug(1, "Waiting for decode");
+            packetqueue.notify_all(); // decode might be waiting
             packet_lock->wait();
             if (!snap->image and snap->decoded) {
               Debug(1, "No image but was decoded, giving up");

src/zm_packetqueue.h

@@ -81,6 +81,7 @@ class PacketQueue {
     );
     bool is_there_an_iterator_pointing_to_packet(const std::shared_ptr<ZMPacket> &zm_packet);
     void unlock(ZMLockedPacket *lp);
+    void notify_all() { condition.notify_all(); };
 };
 
 #endif /* ZM_PACKETQUEUE_H */