Now that the FFU process relies on the upgrade_tasks and deployment
tasts there is no need to keep the old fast_forward_upgrade_tasks.
This patch removes all the fast_forward_upgrade_tasks section from
the services, as well as from the common structures.
Change-Id: I39b8a846145fdc2fb3d0f6853df541c773ee455e
(cherry picked from commit 8783ec9c45)