Add spaces around operators. Signed-off-by: Zhang Han <zhanghan64@huawei.com> Message-Id: <20201228071129.24563-4-zhanghan64@huawei.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Markus Armbruster <armbru@redhat.com>