ADIOS: change subclassing from Package to AutotoolsPackage (#3230)
ADIOS: change subclassing from Package to AutotoolsPackage (#3230)

* ADIOS: change the invocation of python script that generates test files

The python script ADIOS*/utils/gpp/gpp.py is invoked directly in the
ADIOS*/tests/genarray/Makefile and the name of the python interpreter
can be quite long if it is one built under spack, i.e. longer than the
80 characters allowed by the #! line in bash.  The name of the shbang
line is truncated at 80 characters and bash cannot find the python
interpreter specified.

This fix changes how the script is executed, by invoking it under
python. This way, the shbang line is ignored.

* adios: fixed flake8 errors from previous commit.

* adio: Switch to AutotoolsPackage class from Package class

Switched in order to add support for the ppc64le platform.

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