Since split_footers became more resilient to malformed
footers and started returning the entire last paragraph,
instead of just the last paragraph iff it was entirely
well-formed, other functions like remove_footer need to
make sure they handle the case where not every line of
the footer paragraph can be parsed.

R=iannucci@chromium.org

Bug: 740601
Change-Id: I75c6c626d96942181f453abeee896ee92d14b20b
Reviewed-on: https://chromium-review.googlesource.com/565779Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Aaron Gable <agable@chromium.org>