In a nutshell, since a circuit can not exit at its entry point, it's very
easy for an attacker to find the hidden service guard if only one EntryNodes
is specified since for that guard, the HS will refuse to build a rendezvous
circuit to it.
For now, the best solution is to stop tor to allow a single EntryNodes for
an hidden service.
Fixes#14917
Signed-off-by: David Goulet <dgoulet@ev0ke.net>