Use auto for unique pointers

samples/iptcprint.cpp

@@ -18,8 +18,7 @@ try {
         return 1;
     }
 
-    Exiv2::Image::UniquePtr image = Exiv2::ImageFactory::open(argv[1]);
-    assert (image.get() != 0);
+    auto image = Exiv2::ImageFactory::open(argv[1]);
     image->readMetadata();
 
     Exiv2::IptcData &iptcData = image->iptcData();