Added check to ensure compatible libcouchbase version is being used.

Change-Id: Iee59604c6a5bc0f8d8a0ed7be0364e4a0a8b5ed6
Reviewed-on: http://review.couchbase.org/28697
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Brett Lawson <brett19@gmail.com>