[IPOL discuss] Corrected concurrent executions bug

[Miguel Colom]

Dear all,
today we have corrected an ugly bug related to a race condition in the  
demo system.

If you're executing a workshop in the Purple server (development), you  
should update the following file: lib/base_app.py

You can either change your local file by this one
http://dev.ipol.im/~colom/base_app.py

or you can do a "git pull origin master" where origin is the official  
IPOL demo system code, if you're using git.

Remember to stop and restart the demo server after the file change.

This change affects only to the core demo system, and therefore the  
code of the demos doesn't need to be modified.

Best,
Miguel