MB-100: make xmem error logs more user-friendly

QE mentioned it is not clear how to read the XMem stat in the
"XDCR errors" on UI. This commit will explain these stats to
make it more use-friendly. E.g, if xmem worker crashed due to
remote memcached errors, we will see something like this on UI:

"xmem stats: in batch of 500 docs: flushed: 460, rejected
(eexists): 10; remote memcached errors: enoent: 20, not-my-vb: 5,
invalid: 0, timeout: 5, others: 0."

Change-Id: I3d42832a589a21c5c072819516eeaec68b3f4d30
Reviewed-on: http://review.couchbase.org/28579
Tested-by: Junyi Xie <junyi.couchbase@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
MB-100 Make menelaus_ui_auth ets tables protected.

For easier debugging.

Change-Id: I0a92fa424c0f057c7eefb5e06b791aad1dbcd870
Reviewed-on: http://review.couchbase.org/28604
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-8815 Fix RO user access to auth_any_bucket endpoints.

This didn't work if there were no buckets defined.

Change-Id: I0693715c3a92d3f97e8c135265fdb056796236fc
Reviewed-on: http://review.couchbase.org/28605
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
MB-8974 suppress unnecessary error messages in cbreset_password

- do not display failed attempts to read initargs if one of the
  attempts succeeded
- suppress confusing stderr output from erl shell script on mac

Change-Id: Ibe75411caddb21e209734345ee246a9a85764541
Reviewed-on: http://review.couchbase.org/28606
Tested-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Merge remote-tracking branch 'couchbase/2.2.0'

* couchbase/2.2.0:
  MB-8974 suppress unnecessary error messages in cbreset_password
  MB-8815 Fix RO user access to auth_any_bucket endpoints.
  MB-100 Make menelaus_ui_auth ets tables protected.
  MB-100: make xmem error logs more user-friendly

Change-Id: I1bde1543fe691ec21d8e6dfab2ddc0bfedd40b4e