Python 3 compatibility syntax error fixes (#10519)

* Use Python 3 style print function

* Use 'Exception as e' instead of 'Exception, e'

* Unpack tuple arguments explicitly in instead of relying on auto unpacking

* Use consistent indentation

* Use 0 if stock_frozen_upto_days is None
diff --git a/erpnext/templates/utils.py b/erpnext/templates/utils.py
index e46fed6..6ebe411 100644
--- a/erpnext/templates/utils.py
+++ b/erpnext/templates/utils.py
@@ -36,11 +36,11 @@
     ))
 
     if customer:
-    	opportunity.customer = customer[0][0]
+        opportunity.customer = customer[0][0]
     elif lead:
-    	opportunity.lead = lead
+        opportunity.lead = lead
     else:
-    	opportunity.lead = new_lead.name
+        opportunity.lead = new_lead.name
 
     opportunity.insert(ignore_permissions=True)