inventory: Move INVENTORY_ROOT to inventory module

Change-Id: Ic68d4a48ff46002858934e0b9c9b1694a2a17a08
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/pyinventorymgr/inventory_items.py b/pyinventorymgr/inventory_items.py
index 94d8f96..254cd9e 100644
--- a/pyinventorymgr/inventory_items.py
+++ b/pyinventorymgr/inventory_items.py
@@ -99,7 +99,8 @@
             pass
 
     for f in FRUS.keys():
-        obj_path = f.replace("<inventory_root>", System.INVENTORY_ROOT)
+        import obmc.inventory
+        obj_path = f.replace("<inventory_root>", obmc.inventory.INVENTORY_ROOT)
         obj = InventoryItem(bus, obj_path, FRUS[f])
         obj_parent.add(obj_path, obj)