Revert "Allow a direct write mode"

This patch is not needed anymore

This reverts commit ecef9852806b397a41fdd223a5ef85de80be2514.

Change-Id: I9450c9ad7117b33a496d0626df294eaace318d70
Reviewed-on: http://review.couchbase.org/25779
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>