Simplify VM scripts for release (rebased onto dev_5_0) (rebased onto develop)



This is the same as gh-1968 but rebased onto develop.

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This is the same as gh-1950 but rebased onto dev_5_0.

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4.4 and 5.0 release jobs have been using
https://gist.github.com/joshmoore/6902157
for some time. Primarily, this patch uses
an existing server zip rather than attempting
to download from a job.

/cc @manics @sbesson

The release job will need to be updated once this is merged.