fix unittesting
    
    setup.py test fails with
    ...
      File "/usr/lib/python2.7/site-packages/setuptools/command/test.py", line 164, in run_tests
        testLoader = cks
      File "/usr/lib64/python2.7/unittest/main.py", line 94, in __init__
        self.parseArgs(argv)
      File "/usr/lib64/python2.7/unittest/main.py", line 149, in parseArgs
        self.createTests()
      File "/usr/lib64/python2.7/unittest/main.py", line 158, in createTests
        self.module)
      File "/usr/lib64/python2.7/unittest/loader.py", line 128, in loadTestsFromNames
        suites = [self.loadTestsFromName(name, module) for name in names]
      File "/usr/lib64/python2.7/unittest/loader.py", line 91, in loadTestsFromName
        module = __import__('.'.join(parts_copy))
    ImportError: No module named runtests