Initialize ipv{4,6}_traffic_ok in entry_connection_new

Initialize ipv{4,6}_traffic_ok in entry_connection_new

This one is necessary for sending BEGIN cells with sane flags when
self-testing a directory port.  All real entry connections were
getting their ipv{4,6}_traffic_ok flags set from their listeners, and
for begindir entry connections we didn't care, but for directory
self-testing, we had a problem.

Fixes at least one more case of 7493; if there are more lingering
cases of 7493, this might fix them too.

Bug not in any released version of Tor.