fix .ebuilder caching in ETermBase.set_backend(), .make_function()
fix .ebuilder caching in ETermBase.set_backend(), .make_function()

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