inventory: add missing json import

Change-Id: I89215bdaf5aa02d0063b6164454b56a7cc19cb37
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/pyinventorymgr/inventory_items.py b/pyinventorymgr/inventory_items.py
index 16ae6d0..c815b37 100644
--- a/pyinventorymgr/inventory_items.py
+++ b/pyinventorymgr/inventory_items.py
@@ -3,6 +3,7 @@
 import os
 import sys
 import gobject
+import json
 import dbus
 import dbus.service
 import dbus.mainloop.glib