Add hexversion to list of safe sys names (SF bug 621447).

Bug fix candidate.

Lib/rexec.py

@@ -143,7 +143,7 @@ class RExec(ihooks._Verbose):
                       'stat', 'times', 'uname', 'getpid', 'getppid',
                       'getcwd', 'getuid', 'getgid', 'geteuid', 'getegid')
 
-    ok_sys_names = ('ps1', 'ps2', 'copyright', 'version',
+    ok_sys_names = ('ps1', 'ps2', 'copyright', 'version', 'hexversion',
                     'platform', 'exit', 'maxint')
 
     nok_builtin_names = ('open', 'file', 'reload', '__import__')