Harmonize usage of "make veryclean" and "make localclean" in packages SOURCES
Each package in the rudder-packages git repo has a directory named "SOURCES" that contains a Makefile that helps fetch any required sources and dependencies, and prepare them for building the packages.
This Makefile has two handy targets: "make localclean" and "make veryclean". The difference is meant to be that "make localclean" removes any generated files, and make veryclean will remove anything that's not supposed to be commited in git.
However, this is currently a bit mix-and-matched, so I'm going to clean it up.
Harmonize usage of "make veryclean" and "make localclean" in packages SOURCES. Fixes #2224