Usage of EXIT_SUCCESS/FAILURE instead of hard-coded values

samples/iptceasy.cpp

@@ -14,7 +14,7 @@ int main(int argc, char* const argv[]) try {
 
   if (argc != 2) {
     std::cout << "Usage: " << argv[0] << " file\n";
-    return 1;
+    return EXIT_FAILURE;
   }
   std::string file(argv[1]);
 
@@ -41,8 +41,8 @@ int main(int argc, char* const argv[]) try {
   image->setIptcData(iptcData);
   image->writeMetadata();
 
-  return 0;
+  return EXIT_SUCCESS;
 } catch (Exiv2::Error& e) {
   std::cout << "Caught Exiv2 exception '" << e << "'\n";
-  return -1;
+  return EXIT_FAILURE;
 }