update test_eigenvalue_solvers.py for pytest
update test_eigenvalue_solvers.py for pytest

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