flow/manager: Fix condition for wg.Done().
flow/manager: Fix condition for wg.Done().

Change-Id: Id0dd4259011f36cde336a3e5e0488e7c6000d23a

vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref,vanadium/go.ref