Fix wrong choice of driver

Author: alex-kulakov

Orm/Xtensive.Orm.MySql/Sql.Drivers.MySql/DriverFactory.cs

@@ -122,7 +122,7 @@ private static SqlDriver CreateDriverInstance(string connectionString, Version v
         5 when version.Minor == 1 => new v5_1.Driver(coreServerInfo),
         5 when version.Minor == 5 => new v5_5.Driver(coreServerInfo),
         5 when version.Minor == 6 => new v5_6.Driver(coreServerInfo),
-        5 when version.Major == 7 => new v5_7.Driver(coreServerInfo),
+        5 when version.Minor == 7 => new v5_7.Driver(coreServerInfo),
         6 => throw new NotSupportedException(),
         7 => throw new NotSupportedException(),
         8 => new v8_0.Driver(coreServerInfo),