small tweak in Region.get_cells()
small tweak in Region.get_cells()

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