when counting keyframe interval in clearPackets start at 0. Reset max_keyframe_interval when clearing packetqueue. This prevents errors in log when using ondemand capture

src/zm_packetqueue.cpp

@@ -295,7 +295,7 @@ void PacketQueue::clearPackets(const std::shared_ptr<ZMPacket> &add_packet) {
     return;
   }
 
-  int keyframe_interval_count = 1;
+  int keyframe_interval_count = 0;
   int video_packets_to_delete = 0;    // This is a count of how many packets we will delete so we know when to stop looking
 
   ZMLockedPacket *lp = new ZMLockedPacket(zm_packet);
@@ -428,6 +428,7 @@ void PacketQueue::clear() {
   delete[] packet_counts;
   packet_counts = nullptr;
   max_stream_id = -1;
+  max_keyframe_interval_ = 0;
 
   Debug(1, "Packetqueue is clear, notifying");
   condition.notify_all();