rename StandardError to Exception

StandardError was removed in Python 3, see [1].
The recommended fixer will replace all uses of StandardError with Exception.

1. https://docs.python.org/3/whatsnew/3.0.html

Author: ligurio

tarantool/error.py

@@ -26,7 +26,7 @@
 
 
 try:
-    class Warning(StandardError):
+    class Warning(Exception):
         '''Exception raised for important warnings
         like data truncations while inserting, etc. '''
 except NameError:
@@ -35,7 +35,7 @@ class Warning(Exception):
         like data truncations while inserting, etc. '''
 
 try:
-    class Error(StandardError):
+    class Error(Exception):
         '''Base class for error exceptions'''
 except NameError:
     class Error(Exception):