update test_install.py for Python 3
update test_install.py for Python 3

sfepy/sfepy,vlukes/sfepy,sfepy/sfepy,vlukes/sfepy,rc/sfepy,BubuLK/sfepy,BubuLK/sfepy,lokik/sfepy,lokik/sfepy,BubuLK/sfepy,rc/sfepy,lokik/sfepy,sfepy/sfepy,rc/sfepy,vlukes/sfepy,lokik/sfepy