fix default logging levels to NOTICE, not DEBUG

Tweak unit test binaries to still used DEBUG loglevels, so that their expected
outputs remain unchanged (and nicely verbose).

Adjust test_nodes.vty, now expecting the 'notice' log levels upon
'show running-config'.

Change-Id: Ic061e61c9625b49cef8bc2a2c0b936e262c22268
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index 0de4ff4..6de673a 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -101,9 +101,9 @@
   logging print category 1
   logging print extended-timestamp 1
   logging level all debug
-  logging level main debug
-  logging level db debug
-  logging level auc debug
+  logging level main notice
+  logging level db notice
+  logging level auc notice
 ...
 !
 line vty