Remove python26 jobs from all stackforge projects

Remove python26 jobs from all stackforge projects since we're
deprecating it.

As discussed in the infra meeting on 2014-10-21:
If projects still need it the python jobs, they have to manually add
them back and the infra team will review these patches.

Change-Id: If103babfe6c39ca07d4ddb4bc76ff43efd72a603
Merge "Remove python26 jobs from all stackforge projects"