Fix oppulance

If starting from scratch the archive file isn't there in do_fetch; in this case, we can make use of the folder where the freshly downloaded resources are cloned to.

mentioned in merge request !73 (merged)

merged

mentioned in commit 57bec9cf

Hi @emuller,

It failed here:
https://gitlab.ebrains.eu/technical-coordination/project-internal/devops/platform/ebrains-spack-builds/-/jobs/27278

spack-build-out.txt

Thx, this seems to be an incompatibility between the version of binutils-gdb and flex… we'll investigate internally.

And the dependency on flex should be fixed by !95 (merged).