fixup! fixup! Bug 40166: Update apt cache before calling pre_pkginst in container-image config

projects/container-image/config

@@ -27,11 +27,15 @@ pre: |
   # [% c('var/container/suite') %]
   set -e
   export DEBIAN_FRONTEND=noninteractive
+  # Update the package cache so the container installs the most recent
+  # version of required packages.
   apt-get update -y -q
   [% IF pc(c('origin_project'), 'var/pre_pkginst') -%]
   [% pc(c('origin_project'), 'var/pre_pkginst') %]
-  [% END -%]
+  # Update the package cache again because `pre_pkginst` may change the
+  # package manager configuration.
   apt-get update -y -q
+  [% END -%]
   apt-get upgrade -y -q
   [%
      deps = [];