Hide 'bucket' and 'host' options

Should be specified via dsn instead

Change-Id: I58df6ff1be290919f0efe7c0072ac3022600b0cd
Reviewed-on: http://review.couchbase.org/38742
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>