Use get_spec in relocated _try_install_from_binary_cache (#15131)
Use get_spec in relocated _try_install_from_binary_cache (#15131)

* Use get_spec in relocated _try_install_from_binary_cache

LLNL/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,iulian787/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack