MB-100: don't mention erlang when refusing "dotless" hostnames

We do in fact refuse because of erlang, but it was said that it's
better to just say we require fqdn, not erlang which looks like some
complain.

Change-Id: Iaf3dd4cdeda186ea874a2e79c0b6a9969ece0455
Reviewed-on: http://review.couchbase.org/26958
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
MB-100: collect diags before logs

So that if grabbing diag fails we have some clues in logs

Change-Id: Ib01650dd7f72b5b7c7369b0ba9383fe6efa7c14a
Reviewed-on: http://review.couchbase.org/26959
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
MB-8433: don't lose rebalance progress stats on ff map reset

In MB-8433 we observed complete reset of rebalance observer state, and
from closer code inspection we found it was caused by fast-forward map
reset that completes bucket rebalance.

Trivial fix is to only do initiate_bucket_rebalance only on first
fast-forward map update for bucket.

Change-Id: I9b19fefe7c555c6328f8ac093fb922ffeaabc50e
Reviewed-on: http://review.couchbase.org/26960
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
MB-100: updated bucket workers bucket restart warning

As suggested by Dipti

Change-Id: I6cd9ddf0a9ae7c3a2e624ac134defe8adf761164
Reviewed-on: http://review.couchbase.org/26961
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Merge remote-tracking branch 'origin/2.1.1'

* origin/2.1.1:
  MB-100: updated bucket workers bucket restart warning
  MB-8433: don't lose rebalance progress stats on ff map reset
  MB-100: collect diags before logs
  MB-100: don't mention erlang when refusing "dotless" hostnames

trivial merge

Change-Id: I443f2edece9cf4ce8084da0ff358164327ba7402