Fix: close intro circuit if no more intro points are usable

Once a NACK is received on the intro circuit, tor tries an other usable one
by extending the current circuit to it. If no more intro points are usable,
now close the circuit. Also, it's reason is changed before closing it so we
don't report again an intro point failure and trigger an extra HS fetch.

Fixes #14224

Signed-off-by: David Goulet <dgoulet@ev0ke.net>