Avoid key error when env var is unset
Avoid key error when env var is unset

TheTimmy/spack,LLNL/spack,LLNL/spack,krafczyk/spack,iulian787/spack,tmerrick1/spack,EmreAtes/spack,TheTimmy/spack,lgarren/spack,mfherbst/spack,iulian787/spack,TheTimmy/spack,EmreAtes/spack,lgarren/spack,iulian787/spack,matthiasdiener/spack,krafczyk/spack,mfherbst/spack,tmerrick1/spack,krafczyk/spack,TheTimmy/spack,LLNL/spack,matthiasdiener/spack,mfherbst/spack,TheTimmy/spack,skosukhin/spack,skosukhin/spack,matthiasdiener/spack,krafczyk/spack,matthiasdiener/spack,matthiasdiener/spack,tmerrick1/spack,mfherbst/spack,lgarren/spack,iulian787/spack,LLNL/spack,mfherbst/spack,tmerrick1/spack,krafczyk/spack,EmreAtes/spack,iulian787/spack,lgarren/spack,skosukhin/spack,EmreAtes/spack,skosukhin/spack,skosukhin/spack,EmreAtes/spack,lgarren/spack,tmerrick1/spack,LLNL/spack