profile: never save a '?' as default avatar

Change-Id: I27a64040f049d921acf667b895d58a2e25e9fe52
Reviewed-by: Kateryna Kostiuk <kateryna.kostiuk@savoirfairelinux.com>

src/delegates/ImageManipulationDelegate.mm

@@ -196,7 +196,7 @@ namespace Interfaces {
         const bool ret = image.loadFromData(QByteArray::fromBase64(data),type.toLatin1());
         if (!ret) {
             qDebug() << "vCard image loading failed";
-            return drawDefaultUserPixmap(decorationSize, '?', '?');
+            return QVariant();
         }
 
         return QPixmap::fromImage(image);
@@ -299,7 +299,7 @@ namespace Interfaces {
                 }
             }
         } catch (const std::out_of_range& e) {
-            return drawDefaultUserPixmap(size, '?', '?');
+            return QVariant();
         }
     }
 
@@ -481,7 +481,7 @@ namespace Interfaces {
         Q_UNUSED(acc)
         if (auto pro = ProfileModel::instance().selectedProfile())
             return contactPhoto(pro->person(), decorationSize);
-        return drawDefaultUserPixmap(decorationSize, '?', '?');
+        return QVariant();
     }
 
 } // namespace Interfaces