Handle empty VolumeIdentifier in MTP devices.

Issue #1397

ChangeLog

@@ -29,6 +29,7 @@
 19. Change toolbar colours if palette changes.
 20. Add another qt5ct palette work-around.
 21. Don't stop library scan just because of failure in 1 directory.
+22. Handle empty VolumeIdentifier in MTP devices.
 
 2.3.2
 -----

devices/mtpdevice.cpp

@@ -580,6 +580,12 @@ void MtpConnection::updateStorage()
         LIBMTP_devicestorage_struct *s=device->storage;
         while (s) {
             QString volumeIdentifier=QString::fromUtf8(s->VolumeIdentifier);
+            if (volumeIdentifier.isEmpty()) {
+                volumeIdentifier=QString::fromUtf8(s->StorageDescription);
+            }
+            if (volumeIdentifier.isEmpty()) {
+                volumeIdentifier="ID:"+QString::number(s->id);
+            }
             QList<Storage>::Iterator it=storage.begin();
             QList<Storage>::Iterator end=storage.end();
             for ( ;it!=end; ++it) {