Fix regression of install -j.
Fix regression of install -j.

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