Comment 0 for bug 1948507

The utility function 'qos_min_feature_name' computes the QOS by concatenating a prefix to a node name. However, under some circumstances, it's possible that the node name is `None`, thus raising a TypeError. This can happen for example, if the 'storage.aggregate' feature is not present (or the user doesn't have privileges for it), which leads to an always-None node_name (see the method '_get_ssc_aggregate_info' in volume/drivers/netapp/utils/capabilities:270)

An easy fix is to check for `None`, and if so, return an empty string.