Use the correct resource to serialize comments in the review_reply webhook
Use the correct resource to serialize comments in the review_reply webhook

My fix for the review_reply_published webhook event fixed the main
serialization, but the comments were still using the wrong resources. This
change fixes those.

Testing done:
Ran unit tests.

Reviewed at https://reviews.reviewboard.org/r/7755/

sgallagher/reviewboard,reviewboard/reviewboard,davidt/reviewboard,reviewboard/reviewboard,reviewboard/reviewboard,brennie/reviewboard,brennie/reviewboard,chipx86/reviewboard,sgallagher/reviewboard,davidt/reviewboard,chipx86/reviewboard,brennie/reviewboard,sgallagher/reviewboard,brennie/reviewboard,chipx86/reviewboard,reviewboard/reviewboard,chipx86/reviewboard,davidt/reviewboard,sgallagher/reviewboard,davidt/reviewboard