Revert "fly_qgc_mission: link to json11"
Revert "fly_qgc_mission: link to json11"

This reverts commit e9573a6f104efab5d200fcc5f9c000bfc90bc1e8.

dronecore/DroneCore,dronecore/DroneCore,dronecore/DroneCore,dronecore/DroneCore