vCard: send compressed avatar

- load only files in PNG or JPEG format
- if image loading failed skip sending image

Change-Id: I61fe83b8f16bb942a76cd14eb55e1ad1cb10ac17

src/authority/storagehelper.cpp

@@ -143,18 +143,14 @@ QString
 compressedAvatar(const QString& image)
 {
     QImage qimage;
-#ifdef ENABLE_LIBWRAP
-    auto ret = qimage.loadFromData(QByteArray::fromBase64(image.toUtf8()), 0);
-#else
     // Avoid to use all formats. Some seems bugguy, like libpbf, asking
     // for a QGuiApplication for QFontDatabase
     auto ret = qimage.loadFromData(QByteArray::fromBase64(image.toUtf8()), "JPEG");
     if (!ret)
         ret = qimage.loadFromData(QByteArray::fromBase64(image.toUtf8()), "PNG");
-#endif
     if (!ret) {
         qDebug() << "vCard image loading failed";
-        return image;
+        return "";
     }
     QByteArray bArray;
     QBuffer buffer(&bArray);