Incorrect pdist_scale and gdist_scale for fetch_navigation in local planner

[NorwegianRockCat]

Hello,

I've been playing around with the local planner and Fetch. I based my code off the base_local_planner and was copying the configuration variables over, when I saw this in fetch_navigation/config/move_base.yaml

pdist_scale: 8.0
gdist_scale: 12.0

However, if you look at the (documentation of these parameters)[https://wiki.ros.org/base_local_planner#Trajectory_Scoring_Parameters]. It says that the maximum value is 5.0 for both of them. I checked and indeed, both of these values are restricted to 5.0 when the local_planner plugin is loaded. This means that both path and goal are weighted the same.

Maybe this is a happy accident, but if that is the case, perhaps these values should both be set at 5.0. Otherwise, if there really is a desire to have a 2/3 ratio between pdist_scale and gdist_scale, it might make more sense to have the values be something like (2 and 3)?

I can happily submit a pull request with corrected values, but I suspect others know the robot much better than I do.