cmake: enable ssl, for https downloads
cmake: enable ssl, for https downloads

By default cmake builds its own curl, without SSL support. This
patch enables SSL when building cmake, fixing the following error:

  error: downloading 'https://...' failed

    status_code: 1
    status_string: "Unsupported protocol"
    log: Protocol "https" not supported or disabled in libcurl

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