fix mei_init_conn(), conn_alloc() for no incident entities
fix mei_init_conn(), conn_alloc() for no incident entities

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