tests/installed: Add var-mount.yml destructive test

Closes: #1668
Approved by: cgwalters

tests/installed/tasks/install-git.yml

@@ -8,6 +8,9 @@
   synchronize: src=build/x86_64/ dest=/root/x86_64/ archive=yes
 - name: Install RPMs
   shell: rpm-ostree override replace /root/x86_64/*.rpm
+# Regenerate to make sure new ostree binaries also make it to the initrd
+- name: Regenerate initramfs
+  shell: rpm-ostree initramfs --enable
 - import_tasks: ../tasks/reboot.yml
 - import_tasks: ../tasks/query-host.yml
 - command: ostree --version