[mission] send 0 as dummy type in status instead of 255

sw/airborne/modules/mission/mission.c

@@ -92,7 +92,7 @@ void mission_status_report(void) {
     task_list[j++] = (uint8_t)mission.elements[i].type;
     i = (i+1)%MISSION_ELEMENT_NB;
   }
-  if (j == 0) { task_list[j++] = 255; } // Dummy value if task list is empty
+  if (j == 0) { task_list[j++] = 0; } // Dummy value if task list is empty
   //compute remaining time (or -1. if no time limit)
   float remaining_time = -1.;
   if (mission.elements[mission.current_idx].duration > 0.) {

sw/airborne/modules/mission/mission.h

@@ -34,13 +34,13 @@
 #include "math/pprz_geodetic_float.h"
 
 enum MissionType {
-  MissionWP,
-  MissionCircle,
-  MissionSegment,
-  MissionPath,
-  MissionSurvey,
-  MissionEight,
-  MissionOval
+  MissionWP = 1,
+  MissionCircle = 2,
+  MissionSegment = 3,
+  MissionPath = 4,
+  MissionSurvey = 5,
+  MissionEight = 6,
+  MissionOval = 7
 };
 
 enum MissionInsertMode {