Revert "Improve cleanup.sh script"

This reverts commit 992b08c.

packer/scripts/cleanup.sh

@@ -1,8 +1,6 @@
 echo "cleaning up apt"
 apt-get -y autoremove
 apt-get -y clean
-apt-get -y autoclean all
-rm -rf /var/lib/apt/lists/*
 
 echo "cleaning up guest additions"
 rm -rf VBoxGuestAdditions_*.iso VBoxGuestAdditions_*.iso.?
@@ -16,8 +14,5 @@ mkdir /etc/udev/rules.d/70-persistent-net.rules
 rm -rf /dev/.udev/
 rm /lib/udev/rules.d/75-persistent-net-generator.rules
 
-echo "removing unneeded source files"
-rm -rf /usr/src/*
-
-echo "remove documentation"
-rm -rf /usr/share/doc/* /usr/share/lintian/* /usr/share/linda/* /var/cache/man/*
+echo "removing headers"
+rm -rf /usr/src/linux-headers*