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: Iedaf4612d406450a2fc25e6066e325aa137915cf
Reviewed-on: http://review.couchbase.org/42893
Reviewed-by: Volker Mische <volker.mische@gmail.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sarath Lakshman <sarath@couchbase.com>