Restarting should just start the server if one isn't already running.

Summary: I think this behavior is more convenient. It would have made testing
the saved state behavior easier, for one. Also, things like `service` on Linux
operate the same way.

Reviewed By: @elgenie

Differential Revision: D1704053

Signature: t1:1704053:1416995526:7d02ea3d138445566fb38dc9aab3c73a15b809de