base: fix (not) caching deb files

The Debian slim variant already disabled the cache, so don't interfere.

base/rootfs/etc/apt/apt.conf.d/99local

@@ -1,4 +1,2 @@
-Dir::Cache "";
-Dir::Cache::archives "";
 APT::Install-Recommends "false";
 APT::Install-Suggests "false";

base/rootfs/usr/bin/apt-cleanup

@@ -1,4 +1,3 @@
 #!/bin/sh
 
-rm -f /*.deb
 rm -rf /var/lib/apt/lists/