cephclient wrapper is converting a flat list of dictionaries returned
by Ceph Mimic's osd_crush_tree() to nested dictionaries (actual tree)
as expected sysinv. While doing this it looks at the "children"
attribute and if there's none then it skips populating current
For storage nodes that don't have any attached OSDs the corresponding
tree entry will not have an "items" attribute. When sysinv tries to
get OSD's by storage it tries to access it and crashes.
Fix by creating empty "items" attribute unless node type is "osd".
Signed-off-by: Daniel Badea <email@example.com>