qemu: migration: Forbid tunnelled non-shared storage migration with -blockdev
qemu: migration: Forbid tunnelled non-shared storage migration with -blockdev

qemu's internals were not prepared for switching to -blockdev for the
legacy storage migration. Add a proper error message since qemu is
unlikely to attempt fixing the old protocol.

Resolves: https://gitlab.com/libvirt/libvirt/-/issues/65
Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

jfehlig/libvirt,crobinso/libvirt,zippy2/libvirt,libvirt/libvirt,jfehlig/libvirt,jfehlig/libvirt,nertpinx/libvirt,zippy2/libvirt,jfehlig/libvirt,nertpinx/libvirt,libvirt/libvirt,crobinso/libvirt,crobinso/libvirt,nertpinx/libvirt,libvirt/libvirt,olafhering/libvirt,nertpinx/libvirt,nertpinx/libvirt,libvirt/libvirt,zippy2/libvirt,crobinso/libvirt,olafhering/libvirt,olafhering/libvirt,zippy2/libvirt,olafhering/libvirt