You could stop it from running by changing S20tor to K20tor in /etc/rc2.d
through /etc/rc.5
$ ls /etc/rc2.d
README S20hddtemp S20speech-dispatcher S70pppd-dns
S16openvpn S20postfix S20tor S91apache2
S19mysql S20rsync S25mdadm S99ondemand
S20clamav-freshclam S20screen-cleanup S37iptables-persistent S99rc.local
$ sudo mv /etc/rc2.d/S20tor /etc/rc2.d/K20tor
and repeat for /etc/rc.3.d and so forth. On mine rc0.d, rc1.d and rc6.d all
have the Kill tor K20tor but run levels 3 through 5 have the start flag
S20tor.
If you make them all K20tor and reboot it shouldn't start.
This is an easier way.
...I ran this on mine
$ sudo update-rc.d tor disable
[sudo] password for geshmy:
update-rc.d: warning: start runlevel arguments (none) do not match tor
Default-Start values (2 3 4 5)
update-rc.d: warning: stop runlevel arguments (none) do not match tor
Default-Stop values (0 1 6)
Disabling system startup links for /etc/init.d/tor ...
Removing any system startup links for /etc/init.d/tor ...
/etc/rc0.d/K20tor
/etc/rc1.d/K20tor
/etc/rc2.d/S20tor
/etc/rc3.d/S20tor
/etc/rc4.d/S20tor
/etc/rc5.d/S20tor
/etc/rc6.d/K20tor
Adding system startup for /etc/init.d/tor ...
/etc/rc0.d/K20tor -> ../init.d/tor
/etc/rc1.d/K20tor -> ../init.d/tor
/etc/rc6.d/K20tor -> ../init.d/tor
/etc/rc2.d/K80tor -> ../init.d/tor
/etc/rc3.d/K80tor -> ../init.d/tor
/etc/rc4.d/K80tor -> ../init.d/tor
/etc/rc5.d/K80tor -> ../init.d/tor
and then
$ sudo update-rc.d tor enable
starts it back up.
