* Fix non-local rack pickle path
Looks like a copy&paste error from/in 57742dbb.
* Optimize download
Use a partial clone, which is supported in Git since 2.18 (released
2018). The amount of actually downloaded data is roughly equal to the
size of the required files, the compression offsets the git overhead.
* Fallback for old git versions
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Co-authored-by: Harry <Harry@cadby.co.uk>
c390a41d82