There's no need to depend on gtk-doc to install .html files. See the tracking bug for details.
As long as there is no other package to own /usr/share/gtk-doc/(html) this is not a bug but follows the guidelines. If you think this is not the case, please figure this out on the packaging list before repoening this bug. So far I don't see a post from you there.
It is a bug, see:
From the original bug #604169 comment #31
Which by my reading means that all packages which place files in
/usr/share/gtk-doc/ should go ahead and own that dir. (root/root, mode 755).
Fixed in http://koji.fedoraproject.org/koji/taskinfo?taskID=2521488