Merge pull request #225 from iansf/ios_logging

Feedback from previous logging code review that I missed.

sky/engine/bindings/builtin_natives.cc

@@ -175,7 +175,7 @@ void Logger_PrintString(Dart_NativeArguments args) {
     // message is discoverable when running on an unrooted device.
     __android_log_print(ANDROID_LOG_INFO, "sky", "%.*s", length, chars);
 #elif __APPLE__
-    syslog(LOG_WARNING, "sky: %.*s", (int)length, chars);
+    syslog(LOG_INFO, "%.*s", (int)length, chars);
 #endif
   }
 }