Comment 0 for bug 1689642

When Adam was looking at [1] bug 1688606, he noted that cloud-initramfs-rooturl
uses squashfs support, and thus should do a:
  manual_add_modules squashfs

Previously it had relied on the fact that either
 a.) Ubuntu kernels have squashfs builtin
 b.) MODULES=most will generally get squashfs other than on precise (LP: #1501834)

[1] https://irclogs.ubuntu.com/2017/05/09/%23ubuntu-release.html

Related bugs:
 * bug 1688606: SRU cloud-initramfs-rooturl to archive