Remove 'syncmode' example

We're not removing syncmode in 2.4 but we certainly don't want to show
this as an acceptable API to be using.

Change-Id: I04290d8f7e82d8c38d5b1d5d9625bb61d793290a
Reviewed-on: http://review.couchbase.org/38799
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>