fix incorrect argc < 1 check for no arguments

-requiring arguments should be argc < 2

src/drivers/ardrone_interface/ardrone_interface.c

@@ -108,8 +108,9 @@ usage(const char *reason)
  */
 int ardrone_interface_main(int argc, char *argv[])
 {
-		if (argc < 1)
+	if (argc < 2) {
 		usage("missing command");
+	}
 
 	if (!strcmp(argv[1], "start")) {
 

src/drivers/hott/hott_sensors/hott_sensors.cpp

@@ -197,7 +197,7 @@ hott_sensors_thread_main(int argc, char *argv[])
 int
 hott_sensors_main(int argc, char *argv[])
 {
-	if (argc < 1) {
+	if (argc < 2) {
 		errx(1, "missing command\n%s", commandline_usage);
 	}
 

src/drivers/hott/hott_telemetry/hott_telemetry.cpp

@@ -223,7 +223,7 @@ hott_telemetry_thread_main(int argc, char *argv[])
 int
 hott_telemetry_main(int argc, char *argv[])
 {
-	if (argc < 1) {
+	if (argc < 2) {
 		errx(1, "missing command\n%s", commandline_usage);
 	}
 

src/drivers/md25/md25_main.cpp

@@ -97,8 +97,9 @@ usage(const char *reason)
 int md25_main(int argc, char *argv[])
 {
 
-	if (argc < 1)
+	if (argc < 2) {
 		usage("missing command");
+	}
 
 	if (!strcmp(argv[1], "start")) {
 

src/drivers/roboclaw/roboclaw_main.cpp

@@ -92,8 +92,9 @@ static void usage()
 int roboclaw_main(int argc, char *argv[])
 {
 
-	if (argc < 1)
+	if (argc < 2) {
 		usage();
+	}
 
 	if (!strcmp(argv[1], "start")) {