Adding OnFail to VASP.

  * Seems to fail otherwise on MacOS running Ubuntu@parallels.
    More specifically, vasp fails at the very end of the run, when it doesn't
    matter.
  * VASP test run now working on tempdir, not /tmp/test/. Also, make sure that
    if set to /tmp/test, the directory is deleted if it exists. E.g. can run
    multiple debug test.