parse_json not python3 compatible
Motivation
----------

String responses cannot be decoded into UTF-8 in Python 3, since they're already UTF-8 by default. The function has been removed from the language.

Modification
------------

provided by @XeBoris

```
def parse_response(data):
   """ JSON render function
   """
   ret_obj = None
   try:
       ret_obj = data.decode('utf-8')
   except AttributeError:
       ret_obj = data
   
   return json.loads(ret_obj)
```
diff --git a/lib/rucio/common/utils.py b/lib/rucio/common/utils.py
index fe7695560..0b1e9f03a 100644
--- a/lib/rucio/common/utils.py
+++ b/lib/rucio/common/utils.py
@@ -272,9 +272,16 @@ def datetime_parser(dct):
 
 
 def parse_response(data):
-    """ JSON render function
     """
-    return json.loads(data.decode('utf-8'), object_hook=datetime_parser)
+    JSON render function
+    """
+    ret_obj = None
+    try:
+        ret_obj = data.decode('utf-8')
+    except AttributeError:
+        ret_obj = data
+
+    return json.loads(ret_obj, object_hook=datetime_parser)
 
 
 def generate_http_error(status_code, exc_cls, exc_msg):
['lib/rucio/common/utils.py']