Update to 14.04 broke python cgi

[Peer]

I have a script using:

import BaseHTTPServer, CGIHTTPServer

[...]

handler_class.cgi_directories=['/cgi', '/cgi/tools']

with some cgis in /cgi and others in /cgi/tools.
All worked fine for years.

All the cgis in /cgi (like http://localhost:8002/cgi/test-cgi.py) contiue to work.
After the update, all the cgis in /cgi/tools (like http://localhost:8002/cgi/tools/test-cgi.py) don't work any more. The only response I get is this error:

Error response
Error code 403.
Message: CGI script is not a plain file ('/cgi/tools').
Error code explanation: 403 = Request forbidden -- authorization will not help.

Of course /cgi/tools is not a plain file, because it's a directory:

~/server-path/cgi$ ls -dl tools/
drwxr-xr-x 2 me me 4096 Jun 6 2013 tools/

So why did this break? How come that the directory /cgi/tools, although declared as cgi directory, has to be a "plain file"?
What changed from 13.10 to 14.04 to produce this?

[Peer (peer-i)]

Sorry, I postet this by error to "baloo".
Don't know how to change the assignment, though. (And don't know where this belongs: python? kubuntu? update?)
Can somebody help with reassignment (or this bug), please?