[logdog] Cast line into a string before emitting
[logdog] Cast line into a string before emitting

fprintf(%s, []byte) produces something that looks like
[12 243 429 589 ....]
It neesd to be a string

Change-Id: Ief962c7ed95fa6736eb4e72dc72375128b193b0d
Reviewed-on: https://chromium-review.googlesource.com/c/1289230
Reviewed-by: Robbie Iannucci <40f3d43a28ebae3cb819288542e1c84d73d962d5@chromium.org>
Commit-Queue: Ryan Tseng <2190fe9a39b4920ec7bd59c848ec5cccd163056f@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go