[PATCH 1/4] testbot: Add Missions support.

[Francois Gouget]

I forgot to mention that this patch requires updating the TestBot 
database schema (I guess it's obvious from the testbot/ddl chunks). So 
after applying this patch and updating the database the Engine and web 
server will need to be restarted.

So the patch add a Missions field to the VMs and Tasks tables. Since the 
Missions field is mandatory update41.sql sets default values. Since I've 
been going back and forth between the pre and post Missions patch in my 
tree update41.sql is careful not to overwrite existing Missions values. 
Hopefully we won't need that on the official TestBot server.

-- 
Francois Gouget <fgouget at codeweavers.com>