torture: Correctly summarize build-only runs

Currently, kvm-recheck.sh complains that qemu failed for --buildonly
runs, which is sort of true given that qemu can hardly succeed if not
invoked in the first place.  Nevertheless, this commit swaps the order
of checks in kvm-recheck.sh so that --buildonly runs will be summarized
more straightforwardly.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>