Open collection config 'r' for py3 compatibility

awx_collection/plugins/module_utils/ansible_tower.py

@@ -91,7 +91,7 @@ def tower_auth_config(module):
         if os.path.isdir(config_file):
             module.fail_json(msg='directory can not be used as config file: %s' % config_file)
 
-        with open(config_file, 'rb') as f:
+        with open(config_file, 'r') as f:
             return parser.string_to_dict(f.read())
     else:
         auth_config = {}