Don't send components version if changing to more stable channel.

When changing to more stable channel and powerwash is allowed, we send
0.0.0.0 as version to Omaha to get an update right away, but there're
also version information in the product components, so we should just
not send those in this case.
Also fixed cpplint warnings in the file touched by this CL.

Test: update_engine_unittests
Change-Id: If43a8dce79d6f59a609cd3306190be3d05dab296