Fix for SPACK-43: compiler finding fails gracefully on unknown error.
Fix for SPACK-43: compiler finding fails gracefully on unknown error.

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