Fix warnings from -Woverloaded-virtual.

git-svn-id: https://znc.svn.sourceforge.net/svnroot/znc/trunk@816 726aef4b-f618-498e-8847-2d620e286838

modules/sample.cpp

@@ -141,7 +141,7 @@ public:
 		return CONTINUE;
 	}
 
-	virtual EModRet OnUserNotice(const CString& sTarget, CString& sMessage) {
+	virtual EModRet OnUserNotice(CString& sTarget, CString& sMessage) {
 		PutModule("[" + sTarget + "] usernotice [" + sMessage + "]");
 		sMessage = "\037" + sMessage + "\037";