'GETINFO config-text' always includes HiddenServiceStatistics

Similar to #2362 (moved), our new HiddenServiceStatistics option always appears in our 'GETINFO config-text' output even if unset...

% cat /tmp/simple_torrc 
ControlPort 9051

% tor-prompt
>>> GETINFO config-text
250+config-text=
ControlPort 9051
DataDirectory /home/atagar/.tor
HiddenServiceStatistics 0
Log notice stdout
.
250 OK

As such saving your torrc in applications like vidalia, arm, and maybe tor browser (does it have the ability to save your torrc?) append this needless option.