changes from @heifner's review of #3190

libraries/chain/include/eosio/chain/abi_def.hpp

@@ -96,7 +96,7 @@ struct error_message {
 
 struct abi_def {
    abi_def() = default;
-   abi_def(const vector<type_def>& types, const vector<struct_def>& structs, const vector<action_def>& actions, const vector<table_def>& tables, const vector<clause_pair>& clauses, vector<error_message>& error_msgs)
+   abi_def(const vector<type_def>& types, const vector<struct_def>& structs, const vector<action_def>& actions, const vector<table_def>& tables, const vector<clause_pair>& clauses, const vector<error_message>& error_msgs)
    :version("eosio::abi/1.0")
    ,types(types)
    ,structs(structs)

libraries/chain/include/eosio/chain/exceptions.hpp

@@ -168,9 +168,9 @@ namespace eosio { namespace chain {
       FC_DECLARE_DERIVED_EXCEPTION( invalid_action_args_exception, action_validate_exception,
                                     3050002, "Invalid Action Arguments" )
       FC_DECLARE_DERIVED_EXCEPTION( eosio_assert_message_exception, action_validate_exception,
-                                    3050003, "Invalid Action Arguments" )
+                                    3050003, "eosio_assert_message assertion failure" )
       FC_DECLARE_DERIVED_EXCEPTION( eosio_assert_code_exception, action_validate_exception,
-                                    3050004, "Invalid Action Arguments" )
+                                    3050004, "eosio_assert_code assertion failure" )
 
    FC_DECLARE_DERIVED_EXCEPTION( database_exception, chain_exception,
                                  3060000, "database exception" )