Fix ipatests.util doc tests
    
    Doctests of ipatests.util fail under Python 3.
    
    The old test scenario does no longer work on Python 3 since u'how are you'
    and 'how are you' have identical type, but u'how are you' != b'how are you'.
    It works with int / float on all Python versions.
    
    Python 2 has <type 'int'> while Python 3 uses <class 'int'>.
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Martin Basti <mbasti@redhat.com>