THRIFT-2506 Update TProtocolException error codes to be used consistently throughout the library

Patch: Jens Geyer
diff --git a/lib/py/src/protocol/TProtocol.py b/lib/py/src/protocol/TProtocol.py
index dc2b095..40e05b1 100644
--- a/lib/py/src/protocol/TProtocol.py
+++ b/lib/py/src/protocol/TProtocol.py
@@ -28,6 +28,8 @@
   NEGATIVE_SIZE = 2
   SIZE_LIMIT = 3
   BAD_VERSION = 4
+  NOT_IMPLEMENTED = 5
+  DEPTH_LIMIT = 6
 
   def __init__(self, type=UNKNOWN, message=None):
     TException.__init__(self, message)