Clean the apt cache at the end of provisioning

The VirtualBox VM is running tight on available space with nearly 100% usage.
This frees things up a bit by cleaning the apt cache after Gitian installation.

roles/common/tasks/update_everything.yml

@@ -42,9 +42,3 @@
   register: autoremove_result
   changed_when: "'0 upgraded' not in autoremove_result.stdout"
   tags: apt
-
-- name: Clean the apt cache.
-  command: apt-get autoclean
-  register: autoclean_result
-  changed_when: "'Del' in autoclean_result.stdout"
-  tags: apt

roles/gitian/tasks/main.yml

@@ -199,6 +199,11 @@
     chdir: "/home/{{ gitian_user }}/gitian-builder"
     executable: /bin/bash
 
+- name: Clean the apt cache to free up space.
+  command: apt-get autoclean
+  register: autoclean_result
+  changed_when: "'Del' in autoclean_result.stdout"
+
 - include: gpg.yml
   tags: gpg
   become: no