MB-20595: Update cbdocloader call to support new docloader
MB-20595: Update cbdocloader call to support new docloader

The new cbdocloader is backwards compatibile with the old one
except we do not accept the BUCKET_USERNAME and BUCKET_PASSWORD
environment variables because they were not needed even in the
old cbdocloader.

We also added a flag for verbose output and to use two client
threads when loading sample data.

Change-Id: I5665090d3562e3c4d654c6631631600914b1c7fe
Reviewed-on: http://review.couchbase.org/66900
Tested-by: Michael Wiederhold <a17fed27eaa842282862ff7c1b9c8395a26ac320@couchbase.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

ceejatec/ns_server,membase/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,ceejatec/ns_server,membase/ns_server,membase/ns_server,ceejatec/ns_server,membase/ns_server,ceejatec/ns_server,membase/ns_server