Improve Ubuntu arch detection (#2649)
Improve Ubuntu arch detection (#2649)

Ubuntu uses a YY.{04,10} release scheme, where YY.04 is not necessarily
binary-compatible with YY.10.
tmerrick1/spack,krafczyk/spack,TheTimmy/spack,skosukhin/spack,lgarren/spack,TheTimmy/spack,matthiasdiener/spack,iulian787/spack,mfherbst/spack,skosukhin/spack,lgarren/spack,iulian787/spack,lgarren/spack,LLNL/spack,EmreAtes/spack,EmreAtes/spack,krafczyk/spack,LLNL/spack,mfherbst/spack,matthiasdiener/spack,TheTimmy/spack,skosukhin/spack,tmerrick1/spack,matthiasdiener/spack,lgarren/spack,iulian787/spack,mfherbst/spack,LLNL/spack,LLNL/spack,EmreAtes/spack,tmerrick1/spack,krafczyk/spack,matthiasdiener/spack,mfherbst/spack,tmerrick1/spack,lgarren/spack,tmerrick1/spack,krafczyk/spack,mfherbst/spack,skosukhin/spack,iulian787/spack,skosukhin/spack,matthiasdiener/spack,EmreAtes/spack,LLNL/spack,TheTimmy/spack,EmreAtes/spack,iulian787/spack,krafczyk/spack,TheTimmy/spack