Fixed some sitl init bugs.

src/modules/simulator/simulator_mavlink.cpp

@@ -463,10 +463,12 @@ void Simulator::pollForMAVLinkMessages(bool publish)
 	char serial_buf[1024];
 
 	struct pollfd fds[2];
+	memset(fds, 0, sizeof(fds));
 	unsigned fd_count = 1;
 	fds[0].fd = _fd;
 	fds[0].events = POLLIN;
 
+
 	if (serial_fd >= 0) {
 		fds[1].fd = serial_fd;
 		fds[1].events = POLLIN;