Test "--device-read-bps" "--device-write-bps" will fail. The root
cause is that GetList helper return empty as its local variable
initialized to zero size.
This patch fix it by setting the related slice size to non-zero.
Signed-off-by: Jianyong Wu <wujianyong@hygon.cn>
Fixes: #5321
(cherry picked from commit 73e78a5822)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>