MB-8012: store deletion timestamp in correct byteorder

Change-Id: Ia2d3f1257cc530e7f81fbe610f44595bd96544b4
Reviewed-on: http://review.couchbase.org/27721
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aaron Miller <apage43@ninjawhale.com>