geofence: remove fence & fence_vertex messages

- this was never read
- it was implemented wrong, leading to memory access violations in
  publishFence (an integer was passed instead of the fence_s struct)

msg/CMakeLists.txt

@@ -55,8 +55,6 @@ set(msg_file_names
 	esc_report.msg
 	esc_status.msg
 	estimator_status.msg
-	fence.msg
-	fence_vertex.msg
 	filtered_bottom_flow.msg
 	follow_target.msg
 	fw_pos_ctrl_status.msg

msg/fence.msg

@@ -1,4 +0,0 @@
-uint8 GEOFENCE_MAX_VERTICES = 16
-
-uint32 count    			# number of actual vertices
-fence_vertex[16] vertices		# geofence positions

msg/fence_vertex.msg

@@ -1,2 +0,0 @@
-float32 lat	# latitude in degrees, worst case float precision gives us 2 meter resolution at the equator
-float32 lon	# longitude in degrees, worst case float precision gives us 2 meter resolution at the equator