gitignore: don't require opt to be a directory
gitignore: don't require opt to be a directory

I use a symlink to make it easy to swap out.

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