[ros-release] Doc build failures

Hi,

We're experiencing some spurrious doc build failures. We're not quite sure
what they are caused by and need some time to look into them. I expect
many of you have received emails in the last few hours. Most of them are
due to this issue. I've turned off the doc builds to keep your inboxes
from filling up with invalid emails. We'll try to find a fix in the
morning.

Tully