Fix server_port can be None #77

Author: pitbulk

src/onelogin/saml2/utils.py

@@ -261,7 +261,7 @@ def get_self_url_host(request_data):
         else:
             protocol = 'http'
 
-        if 'server_port' in request_data:
+        if 'server_port' in request_data and request_data['server_port'] is not None:
             port_number = str(request_data['server_port'])
             port = ':' + port_number