fix the io failure for hotplug-in device

src/modules/battery.cpp

@@ -126,7 +126,14 @@ void waybar::modules::Battery::refreshBatteries() {
           // Ignore non-system power supplies unless explicitly requested
           if (!bat_defined && fs::exists(node.path() / "scope")) {
             std::string scope;
+            try{
+              //for hotplug-in device, access it is always unstable because you may remove the device anytime
+              //so just allow failure happen and do nothing
               std::ifstream(node.path()/"scope")>>scope;
+            }catch(const std::ifstream::failure& e){
+              scope.clear();
+              continue;
+            }
             if (g_ascii_strcasecmp(scope.data(), "device") == 0) {
               continue;
             }