MB-100 Remove unused misc:sys_info{,_collect_loop} functions.

Change-Id: I3a9be67f643e573bb210b8cd464b9faf074f8854
Reviewed-on: http://review.couchbase.org/28930
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>