This patchset changes pegleg's lint function `_verify_deckhand_render`
to render each batch of documents by site, rather than attempting
to render all documents for every site in one go, which results
in false positives.
For example, given 3 sites -- site1, site2, and site3 -- Deckhand
will now render all documents from global, all documents in type,
and all documents in site1, then repeat the same for site2, then
repeat the same for site3, and finally aggregate the error results
from each Deckhand render output, which is returned back to the user.
Change-Id: If853ba0331470d7ec66dfc6116e626251a9f496d
e35cf2c80f