* gitlab: Do not use root_spec['pkg_name'] anymore
For a long time it was fine to index a concrete root spec with the name
of a dependency in order to access the concrete dependency spec. Since
pipelines started using `--use-buildcache dependencies:only,package:never`
though, it has exposed a scheduling issue in how pipelines are
generated. If a concrete root spec depends on two different hashes of
`openssl` for example, indexing that root with just the package name
is ambiguous, so we should no longer depend on that approach when
scheduling jobs.
* env: make sure exactly one spec in env matches hash