Removed unnecessary code in ManyToManyField.deconstruct()

            kwargs['db_table'] = self.db_table

        if self.rel.db_constraint is not True:

            kwargs['db_constraint'] = self.rel.db_constraint

        if "help_text" in kwargs:

            del kwargs['help_text']

        # Rel needs more work.

        if isinstance(self.rel.to, six.string_types):

            kwargs['to'] = self.rel.to