Move init.sh creation to before build and tarball unpacking

[TimoWilken]

See also #800.

This changes a minimum of code, only moving the init.sh creation up in the build script.

[ktf]

Thanks. Indeed environment is simply the creation of the environment file, no?

[TimoWilken]

Yes, exactly!

[TimoWilken]

Actually hang on, I think .build-hash should only be created after a successful build since aliBuild checks for it to see if a previous build has completed.

[ktf]

yes, agreed.

[TimoWilken]

Testing this, there's another problem: when a build fails, the .envrc points to sw/<arch>/<package>/<version>/etc/profile.d/init.sh (which would be correct if the build had succeeded), but it should instead point into $INSTALLROOT and only be changed to point to the former path after the build succeeds.

[TimoWilken]

One more problem: if the build was done in a Docker container (like all the Linux CI builds are), then the paths will only be valid inside the container (i.e., they'll be under /sw, not /build/nomad/.../ci/local/check/sw).

This was a problem before as well, but I suppose at least the .envrc can be used as a base to copy-paste from, filling in the correct paths instead.