job manager: run cfs_update before starting a job

job manager: run cfs_update before starting a job

we may want to even do this only once, before the loop, but for now
this is basically the same as it was previously but avoids the need
for every (future) plugin to do this manually; which is just the
wrong place.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>