nix-prefetch-git: create parent directories

[zgraggen]

Creating nested folders doesn't work with the current mkdir command. Adding the -p option to create parent directories.

[mention-bot]

By analyzing the blame information on this pull request, we identified @bjornfor, @nbp and @timbertson to be potential reviewers

[nbp]

@zgraggen , This modification will cause all the packages which are being fetched from git to be rebuild, thus we cannot accept this patch in master, as this would cause a lot of hashes to change, and this is not good for users who are following the unstable channel.

For mass-rebuild, we have the staging branch, which is where we merge all mass-rebuild changes, and this branch would later be merged in the master branch.

Otherwise the patch sounds good.

[zgraggen]

Thanks for the feedback. So I should create a new pull request against staging?

[abbradar]

Closed by 5e85760. Thanks!

[zgraggen]

Thanks for submitting it for me!