Travis: Don't use mock tests

These builders are extremely slow. Also build without optimizations in
order to make life a bit easier for the builders.

Change-Id: I2374727e931ed6027b280ab8765c8a3d8fffe416
Reviewed-on: http://review.couchbase.org/43652
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Mark Nunberg <mnunberg@haskalah.org>