1. We were sometimes using libevent uninitialized, which is Not Allowed.
2. The malformed-PTR dns test was supposed to get a -1 output... but
the test was wrong, since it forgot that in-addr.arpa addresses
are in reverse order.
Bugs not in any released tor.
These functions must really never fail; so have crypto_rand() assert
that it's working okay, and have crypto_seed_rng() demand that
callers check its return value. Also have crypto_seed_rng() check
RAND_status() before returning.