Theta Star Planner crashes planner server 

Planner server crashes when ThetaStarPlanner is called.  The Planner server works with the DumbPlanner plugin.  Guess the error lies in the ThetaStarPlanner plugin.

```
[ERROR] [planner_server-4]: process has died [pid 1842, exit code -11, cmd '/home/ubuntu/ros_ws/install/nav_drone_planner/lib/nav_drone_planner/planner_server --ros-args -r __node:=planner_server'].
```

