Fix cppcheck warnings

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: Ibe6b12e81292c655f0ab1420159521c2e6991e37
diff --git a/sd_event_loop.cpp b/sd_event_loop.cpp
index ee3395c..ca0def9 100644
--- a/sd_event_loop.cpp
+++ b/sd_event_loop.cpp
@@ -241,12 +241,12 @@
 {
     // set up boost::asio signal handling
     boost::asio::signal_set signals(*io, SIGINT, SIGTERM);
-    signals.async_wait(
-        [this](const boost::system::error_code& error, int signalNumber) {
-            udpSocket->cancel();
-            udpSocket->close();
-            io->stop();
-        });
+    signals.async_wait([this](const boost::system::error_code& /* error */,
+                              int /* signalNumber */) {
+        udpSocket->cancel();
+        udpSocket->close();
+        io->stop();
+    });
 
     startRmcpReceive();