It may happen a base image has an edited version of cloud-init
"cloud.cfg" that prevents the host keys to be generated.
While it didn't represent an issue with older releases of cloud-init,
starting cloud-init-22 this isn't true anymore.
Before that release, an sshd-keygen@.service was present and called by
sshd-keygen.target (which was called by sshd.service), and we ended up
with ssh host keys in any cases - either generated from cloud-init, or
generated by sshd-keygen.service.
But cloud-init-22 introduced an edition to the sshd-keygen.service,
making it check for the presence of cloud-init service, and preventing
this sshd-keygen to kick in this case.
So we'd better ensure cloud-init is able to generate the keys, else
we'll be in a bad state, since it's instructed to remove the ones
present.
Closes-Bug: #1971751
Change-Id: I37b2f3e9d57a86544ef14e74a4a927309c18bbf0
6645f47db4