Fixed #13773 -- Passed in the current connection in a call to db_type()....

            # a second index that specifies their operator class, which is

            # needed when performing correct LIKE queries outside the

            # C locale. See #12234.

            db_type = f.db_type()

            db_type = f.db_type(connection=self.connection)

            if db_type.startswith('varchar'):

                output.append(get_index_sql('%s_%s_like' % (db_table, f.column),

                                            ' varchar_pattern_ops'))