Quiet down log_namer when there is no disk

We don't need to know about all 26 devices every 5 seconds.

Change-Id: Ib350b16c585b08c59bdf690078029464c2764e8a
diff --git a/aos/logging/log_namer.cc b/aos/logging/log_namer.cc
index 22db82a..83a39c8 100644
--- a/aos/logging/log_namer.cc
+++ b/aos/logging/log_namer.cc
@@ -101,7 +101,7 @@
   char test_device[10];
   for (char i = 'a'; i < 'z'; ++i) {
     snprintf(test_device, sizeof(test_device), "/dev/sd%c", i);
-    LOG(INFO) << "Trying to access" << test_device;
+    VLOG(1) << "Trying to access" << test_device;
     if (access(test_device, F_OK) != -1) {
       snprintf(device, device_size, "sd%c", i);
       return true;