trace: display HTTPHandler example at the right place
trace: display HTTPHandler example at the right place

Change-Id: I5b010aafb5d560b06027203b80b0e4218eca8547
Reviewed-on: https://code-review.googlesource.com/12210
Reviewed-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Ross Light <dfccc06f14414bff5a59be7fc90abf4404b47fc8@google.com>

googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go