MB-100: fixed stats timestamp logging

We were incorrectly converting timestamp into local time. Found by
code inspection during CBSE investigation.

Change-Id: I63a2d3654414d04fc9b20b3b4146e3ef1a764165
Reviewed-on: http://review.couchbase.org/24639
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
MB-7670: avoid key order order change in ns_config:update

do_update_rec is processing config pairs in normal order, but prepends
result. Thus it's reversing order of pairs. Thus we're returning
correct order in the end by reversing it again.

Change-Id: Ic9aabfa89dd62e6f8e2481dd3c66f363748e650d
Reviewed-on: http://review.couchbase.org/24640
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
MB-7670: don't save config on empty changes

We've found that janitor's use of ns_config:update caused frequent
saving of same config.

Change-Id: I26ea744767f0daccf77b30ed3fe1d4f63e6206f2
Reviewed-on: http://review.couchbase.org/24641
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
MB-100: clean up timer's kill_after timers

Otherwise they accumulate and cause increased cpu load.

Change-Id: Ic632220e7c257ca9d9f3107a1dcf5f3edc2e23a4
Reviewed-on: http://review.couchbase.org/24642
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-100: introduced ns_config:search_quick/1

Not sure new _additional_ API is good idea, however.

Change-Id: I6579b98a59c11437cf0d857de6ad25ca0e5ce214
Reviewed-on: http://review.couchbase.org/24643
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-100: use quick version of cfg access to check rebalance_status

Change-Id: Ief1af39c4e8067fe37cf2d7e2981355ea81c6d8d
Reviewed-on: http://review.couchbase.org/24644
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>