Downgrade 'Got a certificate, but we already have it' log message from warning to info, except when we're a dirauth (fixes bug 5238)

changes/bug5238

@@ -0,0 +1,3 @@
+ o Minor bugfixes:
+   - Downgrade "Got a certificate, but we already have it" log mesages from
+     warning to info, except when we're a dirauth.

src/or/routerlist.c

@@ -217,9 +217,18 @@ trusted_dirs_load_certs_from_string(const char *contents, int from_store,
        * probably means we wanted a different secret key or we are trying to
        * replace an expired cert that has not in fact been updated. */
       if (!from_store) {
-        log_warn(LD_DIR, "Got a certificate for %s, but we already have it. "
-                 "Maybe they haven't updated it. Waiting for a while.",
-                 ds ? ds->nickname : "an old or new authority");
+        if (authdir_mode(get_options())) {
+          log_warn(LD_DIR,
+                   "Got a certificate for %s, but we already have it. "
+                   "Maybe they haven't updated it. Waiting for a while.",
+                   ds ? ds->nickname : "an old or new authority");
+        } else {
+          log_info(LD_DIR,
+                   "Got a certificate for %s, but we already have it. "
+                   "Maybe they haven't updated it. Waiting for a while.",
+                   ds ? ds->nickname : "an old or new authority");
+        }
+
         authority_cert_dl_failed(cert->cache_info.identity_digest, 404);
       }