OMPL Planners do not work when running study_static_obstacles

[alexperez33]

The OMPL Planners (PRM and RRT*) do not avoid obstacles when study_static_obstacles is run (in both 2D and 3D). This seems to be because the clearance function within the ValidityChecker class is always returning 1e4.

This seems to be because in lines 93 and 108, the code is re-declaring min_dist inside of their respective branch.
double min_dist = 1e4;.
Any modifications to min_dist after this are temporary, and once the branch is exited, the original min_dist value is returned.
Getting rid of lines 93 and 108 allow the OMPL planners to work in the static environments.