Fix problem with broker contract list on PlanetLab

Change-Id: I61bb32dc40b662981116cd6eb0ad237f4fc33260
Reviewed-on: http://naan.mimuw.edu.pl:8001/103
Tested-by: Nebulostore Nebulostore <nebulostore@gmail.com>
Reviewed-by: Bolek Kulbabinski <bkulbabinski@gmail.com>