chore(units): remove deprecated X-Condition from fleet units

See https://github.com/coreos/fleet/blob/19f64d1cec755d6eb01159830e0802b5225d12c8/job/job.go#L23-L37
Merge pull request #40 from carmstrong/fleet_deprecated_X

chore(units): remove deprecated X-Condition from fleet units
fix(units): add fleet.sock bind-mount for controller