control: add missing return after BADREQ in add/rm dep

[nikitax44]

Firstly, I have read and understand the CONTRIBUTING guide in full.

I'm currently building systemd-like nix API on top of dinit.
While implementing a forward-port of SOFT dependency type to a current dinit version I had noticed that these return statements are missing.
(I would like to discuss bringing SOFT dependencies back in a discussion thread later).

If a request with an unknown dependency type is issued, the dinit will respond with BADREQ+ACK and add the invalid dependency to the service's dependency list (which I think is a bug that should be fixed).

[davmac314]

This change looks good, thanks.

(I would like to discuss bringing SOFT dependencies back in a discussion thread later).

You're welcome to do that if it needs further discussion, but note that in general you can get the same effect by introducing a stand-in dependency which depends on the relevant two dependencies.

Eg if you want service A with a soft "dependency" on B, you can instead introduce C (type = internal) which depends-on: A and waits-for: B, and then use C in place of A.