Added log messages in unittest main function.
Added log messages in unittest main function.

Hopefully, these will shed more light on what may be failing and causing
the unittest binary to return an error code.

BUG=chromium-os:29841
TEST=Unittest run with proper log messages.

Change-Id: I6c83c5e8c73590eaafaea3730c8ec1933e7ea8b5
Reviewed-on: https://gerrit.chromium.org/gerrit/21511
Reviewed-by: Richard Barnette <9e7d66387742bf40b0d2548ef2b93e7c522ca0eb@chromium.org>
Commit-Ready: Gilad Arnold <a0dab390cfdc583218cee97b60c5c4eb1be355d2@chromium.org>
Tested-by: Gilad Arnold <a0dab390cfdc583218cee97b60c5c4eb1be355d2@chromium.org>

endocode/update_engine,marineam/update_engine,endocode/update_engine,endocode/update_engine,mjg59/update_engine,marineam/update_engine,mjg59/update_engine,mjg59/update_engine,marineam/update_engine,marineam/update_engine