Add fallback for node 0.10

Improve the fallback mode

index.js

@@ -13,7 +13,16 @@ var net = require("net"),
     connection_id = 0,
     default_port = 6379,
     default_host = "127.0.0.1",
+    debug;
+
+/* istanbul ignore next */
+if (util.debuglog) {
     debug = util.debuglog('redis');
+} else if (/\bredis\b/i.test(process.env.NODE_DEBUG)) {
+    debug = console.error;
+} else {
+    debug = function() {};
+}
 
 // hiredis might not be installed
 try {