verify that internally used headers are not present in incoming request

extra security: to cover a potential hole if in some code path these
headers won't be explicitly set

Change-Id: I98b86a562569cf24979b6e8b9abefe84c8181dd9
Reviewed-on: http://review.couchbase.org/43216
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
use atoms as json keys in audit code for greater efficiency

Change-Id: I57f81abff686eed683e58c87dc8128631e9d27ab
Reviewed-on: http://review.couchbase.org/43217
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
get rid of props_to_json function

to make iolist_to_binary calls explicit in order to allow the value of
the property to be list

Change-Id: I925e5b1732bdc8b0e0dabc05532b876ff32eeb58
Reviewed-on: http://review.couchbase.org/43218
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
allow undefined request in audit api

to support reset_password and potentially node shutdown which are not
initiated by http request

Change-Id: I2abab1aebc29af33b20bd7e9eb388ad89e0d8699
Reviewed-on: http://review.couchbase.org/43219
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
auditing the changes of credentials

Change-Id: I075be154d23735496ca6867758cd8cbbcea76ce9
Reviewed-on: http://review.couchbase.org/43220
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
auditing node operations

Change-Id: Ie5d38b57a0fcd2ac6841e956e2a18a319155751c
Reviewed-on: http://review.couchbase.org/43221
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
auditing rebalance start

Change-Id: Ic3f66ee294eea0119d10b8322c2994c93144c13a
Reviewed-on: http://review.couchbase.org/43222
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>