Tor: Do not attempt to establish connections via IPv6

Tor: Do not attempt to establish connections via IPv6

To quote from the changelog of Tor 0.4.8.4:

  o Minor feature (client, IPv6):
    - Make client able to pick IPv6 relays by default now meaning
      ClientUseIPv6 option now defaults to 1. Closes ticket 40785.

In order to avoid any malfunctions on IPFire installations,
set this option to "0" explicitly.

Signed-off-by: Peter Müller <peter.mueller@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>