new_terms: remove useless code in NewDiffusionTerm
new_terms: remove useless code in NewDiffusionTerm

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