fix some bug for change SN's group

contracts/eosio.system/voting.cpp

@@ -167,13 +167,14 @@ namespace eosiosystem {
 
    void system_contract::rm_producer_seq(const account_name producer, uint16_t seq) {
       
+      
       all_prods_singleton _all_prods(_self, _self);
       all_prods_level     _all_prods_state;
       if (_all_prods.exists()) {
          _all_prods_state = _all_prods.get();
          for( auto it1=  _all_prods_state.prods_l1.begin(); it1 !=  _all_prods_state.prods_l1.end(); it1++ ) {
             if(it1->owner == producer) {
-               _all_prods_state.prods_l2.erase(it1);
+               _all_prods_state.prods_l1.erase(it1);
                break;
             } 
          }