storage: Properly resize a local volume using LUKS
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1490279
    
    Turns out the virStorageBackendVolResizeLocal did not differentiate
    whether the target volume was a LUKS volume or not and just blindly
    did the ftruncate() on the target volume.
    
    Follow the volume creation logic (in general) and create a qemu-img
    resize command to resize the target volume for LUKS ensuring that
    the --object secret is provided as well as the '--image-opts' used
    by the qemu-img resize logic to describe the path and secret ensuring
    that it's using the luks driver on the volume of course.