Fix undefined variable in python3-http-debian template

Functions useing the http-debian tamplate where failing.

The format_response function used an undefined variable 'resp'
this should be 'res'.

Signed-off-by: Han Verstraete (OpenFaaS Ltd) <han@openfaas.com>

Author: welteki

template/python3-http-debian/index.py

@@ -58,7 +58,7 @@ def format_response(res):
     if res == None:
         return ('', 200)
 
-    if type(resp) is dict:
+    if type(res) is dict:
         statusCode = format_status_code(res)
         content_type = get_content_type(res)
         body = format_body(res, content_type)