hobo: handle services without a secret key (#7192)

wcs/ctl/check_hobos.py

@@ -239,6 +239,8 @@ class CmdCheckHobos(Command):
         api_secrets = {}
         for service in self.all_services.get('services', []):
             variables['%s_url' % service.get('slug')] = service.get('base_url')
+            if not service.get('secret_key'):
+                continue
             domain = urlparse.urlparse(service.get('base_url')).netloc.split(':')[0]
             api_secrets[domain] = hashlib.sha1(domain + service.get('secret_key')).hexdigest()
         if self.all_services.get('variables'):