Make test logging more verbose

With the `--verbose` set the test logging output is more verbose.
The output on the screen is still the same it only changes what
gets written to the log file.

Change-Id: Id93658c0c683941e0f3bfb38cd8e9af29929f8c6
Reviewed-on: http://review.couchbase.org/42895
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>