Fix crash for devices without ID_PATH udev property (#1814920)
Fix crash for devices without ID_PATH udev property (#1814920)

In some cases some NVDIMM namespaces don't have the ID_PATH set
and this makes the populate helper crash.

vojtechtrefny/blivet,rvykydal/blivet,jkonecny12/blivet,rvykydal/blivet,jkonecny12/blivet,vojtechtrefny/blivet