Add identifying info (img_timestamp and img_sha1) to upload log.

I came across people complaining that it was hard to associate
upload log events to actual images since img_timestamp could
be different from log_timestamp, and generally no unique id.

Well I was there I made uploads use the new logging system.

Change-Id: Icd8662ecb9eb0f6c0ff9841bdbd5736d6dd0d015