logging: add PageInfo for resource iterator
logging: add PageInfo for resource iterator

Omitted by oversight.

Change-Id: I4b7e9d88cfec031f4313aa9d242075b9902e45d9
Reviewed-on: https://code-review.googlesource.com/7871
Reviewed-by: Jun Mukai <7519e7503d434ad998e9a85ea6f0976705697504@google.com>
Reviewed-by: Sarah Adams <2b342d1c32491b4e7587e4a0e291a5f0f95d4167@google.com>

googleapis/google-cloud-go,michael-grosshans/google-cloud-go,michael-grosshans/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go