do not silently fail if cache is invalid (aka cannot load pickle file)
do not silently fail if cache is invalid (aka cannot load pickle file)

allenh1/rosdep,alessandro-aglietti/rosdep,ros-infrastructure/rosdep,georgepar/rosdep,spaghetti-/rosdep,sorki/rosdep,sorki/rosdep,wkentaro/rosdep,ros-infrastructure/rosdep,aymanim/rosdep,spaghetti-/rosdep,allenh1/rosdep,georgepar/rosdep,alessandro-aglietti/rosdep,aymanim/rosdep,wkentaro/rosdep