Fix exiv2 app: extract, existing file (1. #1934)

Author: postscript-dev

app/actions.cpp

@@ -1718,7 +1718,7 @@ int metacopy(const std::string& source, const std::string& tgt, Exiv2::ImageType
   std::string target(bStdout ? temporaryPath() : tgt);
 
   std::unique_ptr<Exiv2::Image> targetImage;
-  if (Exiv2::fileExists(target)) {
+  if (preserve && Exiv2::fileExists(target)) {
     targetImage = Exiv2::ImageFactory::open(target);
     targetImage->readMetadata();
   } else {