Turning back on binlog checksums by setting the binlog_checksum sys var default value back to CRC32

Author: fulghum

sql/variables/system_variables.go

@@ -388,7 +388,7 @@ var systemVars = map[string]sql.SystemVariable{
 		Dynamic:           true,
 		SetVarHintApplies: false,
 		Type:              types.NewSystemStringType("binlog_checksum"),
-		Default:           "NONE", // TODO: MySQL's default is CRC32
+		Default:           "CRC32",
 	},
 	"binlog_gtid_simple_recovery": &sql.MysqlSystemVariable{
 		Name:              "binlog_gtid_simple_recovery",