Use Item constructor that takes the complete value in toItemWithNoValue
Use Item constructor that takes the complete value in toItemWithNoValue

The function toItemWithNoValue constructs an Item doesn't contain
a value. Instead of using a constructor that take NULL for all
components of value, use a constructor that just takes the whole
value as NULL

Change-Id: I1fd97dab49207240a6949366c8ca2bca1b45381e
Reviewed-on: http://review.couchbase.org/79209
Reviewed-by: Dave Rigby <a09264da4832c7ff1d3bf1608a19f4b870f93750@couchbase.com>
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>

daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine,daverigby/kv_engine