MB-12361:bp: MB-10020 add access.log to /diag and cbcollect_info

Orig-Reviewed-on: http://review.couchbase.org/36842

Conflicts:
	cbcollect_info
	src/diag_handler.erl

This is near-trivial cherry-pick

Change-Id: I07700fd9ed67d2edb268d84c1c583608ef6e9310
Reviewed-on: http://review.couchbase.org/42180
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>