CCBC-558: Always include libuv headers/source with installation

Change-Id: I37444254defc063748b4fff15f088c85c2b9dc66
Reviewed-on: http://review.couchbase.org/44145
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>