If one of the storages passed in $storage_list was not defined get_bandwidth_limit died (see [0], of an occurence of this). This patch changes the behavior to ignore undef as storage instead. [0] https://pve.proxmox.com/pipermail/pve-devel/2019-April/036515.html Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>