don't mark our descriptor dirty if our onion key hasn't changed

changes/bug3263

+  o Minor bugfixes:
+    - Don't publish a new relay descriptor when we reload our onion key,
+      unless the onion key has actually changed. Fixes bug 3263 and
+      resolves another cause of bug 1810. Bugfix on 0.1.1.11-alpha.

src/or/router.c

@@ -82,6 +82,11 @@ static authority_cert_t *legacy_key_certificate = NULL;
 static void
 set_onion_key(crypto_pk_env_t *k)
 {
+  if (onionkey && !crypto_pk_cmp_keys(onionkey, k)) {
+    /* k is already our onion key; free it and return */
+    crypto_free_pk_env(k);
+    return;
+  }
   tor_mutex_acquire(key_lock);
   crypto_free_pk_env(onionkey);
   onionkey = k;