fix broken scuba logging

Summary: Return back to ClientBuild when we're successful so we log CLIENT_BUILD_FINISH.
This isn't a disaster since we still have basically the same data spread out
in scuba table hh_build_steps, but might as well fix this.

Reviewed By: @paulcavallaro

Differential Revision: D1694667

Signature: t1:1694667:1416516191:54be6b1c677a9316acfcbad123e8672a6ea8b35b