clean up tests/test_msm_symbolic.py
clean up tests/test_msm_symbolic.py

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