Add randomness to mocked timestamps.

Change-Id: I027802834b901aeb8bcd5f6d09ade25f0bfd9eca
Reviewed-on: http://review.couchbase.org/35283
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Don't convert ns_config state to 1.6 compatible format.

Because 1.6 is unsupported for a long time.

Change-Id: Iff697886d14f32a2169506e6ae7b0a5ab5eac669
Reviewed-on: http://review.couchbase.org/35284
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-10254 Use latest timestamp to pick the value that looks newer.

vclock:likely_newer considers only common part of vclocks to decide if
one of them is newer than the other one. Hence, instance vclock has no
effect. Which can cause newer value to be overwritten by the older
one (when node is first removed and then added back to cluster).

Change-Id: I310381652201fe18a3de9af3921d9639131cd51b
Reviewed-on: http://review.couchbase.org/35015
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>