NullReferenceException after upgrading MongoDB.Driver to 2.22.0

[molszews]

Due to this commit MongoDB.Driver 2.22.0 will call DocumentVersionService.DetermineVersion() with null passed as the instance parameter causing NullReferenceException. This will happen if linq3 query uses DefaultIfEmpty() clause. There is no easy way to workaround this, seems like null check is needed in MigrationInterceptor before it determines the version