Fixing a bug

samples/cpp/matcher_simple.cpp

@@ -9,7 +9,7 @@ int main(int argc, char** argv)
 {
 	if(argc != 3)
 	{
-		printf("Usage: matches_simple <image1> <image2>\n");
+		printf("Usage: matcher_simple <image1> <image2>\n");
 		return -1;
 	}