Add required json module to the state module

Change-Id: Ia768e35a122ba54ace08ac822215367da747bff7
diff --git a/_states/artifactory.py b/_states/artifactory.py
index ac40b1a..420b58d 100644
--- a/_states/artifactory.py
+++ b/_states/artifactory.py
@@ -4,6 +4,8 @@
 =======================================
 '''
 
+import json
+
 
 def __virtual__():
     if 'artifactory.get_license' in __salt__: