Skip runsvdir-start

Summary:
The runsvdir-start helper isn't shipped anymore with package.

As this script runs the init with configuration, cleaning first the
environment, it's possible to run instead directly runsvdir.

To clean the environment isn't wanted as we configure apps through it.
running directly runsvdir allows to get rid of environment grabbing.

Ref T1679.

Test Plan:
Run containers, check services.

Browse a page with phpinfo(), check environment.

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1679

Differential Revision: https://devcentral.nasqueron.org/D2521