Revert "Only update packages indexes if the cache is 1 hour old"

This reverts commit 201165cff6.

Turns out this actually breaks initial deployments, because the
cache gets updated in the first task, then you add sources for
nginx and mariadb, but it doesn't update the indexes because the
cache is < 3600 seconds old, so you end up getting the distro's
versions of nginx and mariadb.

roles/common/tasks/packages_Ubuntu.yml

@@ -7,7 +7,7 @@
   when: ansible_distribution_version == '14.04'
 
 - name: Upgrade base OS
-  apt: upgrade=dist update_cache=yes cache_valid_time=3600
+  apt: upgrade=dist update_cache=yes
 
 - name: Install base packages
   apt: pkg={{ item }}