Fixed serialization bug

contracts/eosio.system/eosio.system.abi

 {
-  "types": [{
-      "new_type_name": "account_name",
-      "type": "name"
-    }
-  ],
+  "types": [],
   "structs": [{
       "name": "transfer",
       "base": "",

libraries/chain/contracts/chain_initializer.cpp

@@ -72,7 +72,6 @@ abi_def chain_initializer::eos_contract_abi(const abi_def& eosio_system_abi)
    eos_abi.actions.push_back( action_def{name("passrecovery"), "passrecovery"} );
    eos_abi.actions.push_back( action_def{name("vetorecovery"), "vetorecovery"} );
    eos_abi.actions.push_back( action_def{name("onerror"), "onerror"} );
-   eos_abi.actions.push_back( action_def{name("onblock"), "onblock"} );
 
    // ACTION PAYLOADS
 
@@ -302,12 +301,6 @@ abi_def chain_initializer::eos_contract_abi(const abi_def& eosio_system_abi)
       }
    });
 
-   eos_abi.structs.emplace_back( struct_def {
-      "onblock", "", {
-         {"header", "block_header"},
-      }
-   });
-
    return eos_abi;
 }