Iterate over identities in client safely

Change-Id: I65de4d6eb6794100e3046f115324fda71f18e093
diff --git a/glance/client.sls b/glance/client.sls
index 5ae39e0..b7cafcf 100644
--- a/glance/client.sls
+++ b/glance/client.sls
@@ -39,7 +39,7 @@
 
 
 {%- else %}
-{%- for identity_name, identity in client.identity.items() %}
+{%- for identity_name, identity in client.get('identity', {}).items() %}
 
 {%- for image_name, image in identity.image.items() %}