Fix build with exiv2 >=0.28.0.

Index: src/DkCore/DkMetaData.h
--- src/DkCore/DkMetaData.h.orig
+++ src/DkCore/DkMetaData.h
@@ -155,7 +155,7 @@ class DllCoreExport DkMetaDataT (public)
     bool setXMPValue(Exiv2::XmpData &xmpData, QString xmpKey, QString xmpValue);
 
 protected:
-    Exiv2::Image::AutoPtr loadSidecar(const QString &filePath) const;
+    Exiv2::Image::UniquePtr loadSidecar(const QString &filePath) const;
 
     enum {
         not_loaded,
@@ -164,7 +164,7 @@ class DllCoreExport DkMetaDataT (public)
         dirty,
     };
 
-    Exiv2::Image::AutoPtr mExifImg; // TODO std::unique_ptr<Exiv2::Image> (and all other *::AutoPtr)
+    Exiv2::Image::UniquePtr mExifImg; // TODO std::unique_ptr<Exiv2::Image> (and all other *::AutoPtr)
     QString mFilePath;
     QStringList mQtKeys;
     QStringList mQtValues;
