Introduce error_policy=/rerror_policy='retry' to support
werror=/rerror=retry mechanism in qemu.
Add retry_interval parameter to control the interval between retries.
Add retry_timeout parameter to control the total retry times.
Signed-off-by: Jiahui Cen <cenjiahui@huawei.com>
Signed-off-by: Ying Fang <fangying1@huawei.com>