crypto_init() initializes the nonce bloom filter on every call, so a test
that builds a crypto_t per case has to tear it down per case as well.
Freeing only once at the end leaked a pair of filters for every crypto_t
after the first, which the valgrind memcheck job caught.
test_crypto.c already frees it alongside each crypto_t; do the same here
by folding it into the local free_crypto() helper.
Max Lv
fdde2c7cee