Chop another ~93 RSA key generations out of the unit tests

We have a mock for our RSA key generation function, so we now wire
it to pk_generate(). This covers all the cases that were not using
pk_generate() before -- all ~93 of them.

src/common/crypto.c

@@ -984,6 +984,20 @@ crypto_pk_dup_key(crypto_pk_t *env)
   return env;
 }
 
+#ifdef TOR_UNIT_TESTS
+/** For testing: replace dest with src.  (Dest must have a refcount
+ * of 1) */
+void
+crypto_pk_assign_(crypto_pk_t *dest, const crypto_pk_t *src)
+{
+  tor_assert(dest);
+  tor_assert(dest->refs == 1);
+  tor_assert(src);
+  RSA_free(dest->key);
+  dest->key = RSAPrivateKey_dup(src->key);
+}
+#endif
+
 /** Make a real honest-to-goodness copy of <b>env</b>, and return it.
  * Returns NULL on failure. */
 crypto_pk_t *

src/common/crypto.h

@@ -326,5 +326,9 @@ extern int break_strongest_rng_fallback;
 #endif
 #endif
 
+#ifdef TOR_UNIT_TESTS
+void crypto_pk_assign_(crypto_pk_t *dest, const crypto_pk_t *src);
+#endif
+
 #endif