The removal of the mysql.qcow2 image  had a flow-on effect noticed
first by Paul in  that the tools/image_list.sh "sanity" check was
not updated, leading to DIB builds failing in a most unhelpful way as
it tries to cache the images for CI builds.
So while  fixes the problem; one complication here is that the
caching script  loops through the open devstack branches and tries
to collect the images to cache.
Now it seems we hadn't closed the liberty or mitaka branches. This
causes a problem, because the old branches refer to the old image, but
we can't actually commit a fix to change them because the branch is
broken (such as ).
I have taken the liberty of EOL-ing stable/liberty and stable/mitaka
for devstack. I get the feeling it was just forgotten at the time.
Comments in  support this theory. I have also taken the liberty of
approving backports of the fix to newton and ocata branches ,.
A few 3rd-party CI people using dib have noticed this failure. As the
trio of ,, move through, your builds should start working
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