Use LCB_CONFIG_HTTP/MCD_PORT rather than hardcoded literals

Change-Id: Iff6a19ef0653526c27eac0528def5d1333b6b2f6
Reviewed-on: http://review.couchbase.org/34001
Reviewed-by: Brett Lawson <brett19@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>