fix error reporting of finite strain family functions
fix error reporting of finite strain family functions

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