[Bug #758665] cgitb.scanvars() fails because of an unititialized value variable. Patch from Robin Becker.

Author: akuchling

Lib/cgitb.py

@@ -60,7 +60,7 @@ def lookup(name, frame, locals):
 def scanvars(reader, frame, locals):
     """Scan one logical line of Python and look up values of variables used."""
     import tokenize, keyword
-    vars, lasttoken, parent, prefix = [], None, None, ''
+    vars, lasttoken, parent, prefix, value = [], None, None, '', __UNDEF__
     for ttype, token, start, end, line in tokenize.generate_tokens(reader):
         if ttype == tokenize.NEWLINE: break
         if ttype == tokenize.NAME and token not in keyword.kwlist: