qemu: migration: Access job name from job struct
qemu: migration: Access job name from job struct

qemuMigrationSrcNBDCopyCancelOne uses the block job data structure but
generated it's own job name rather than taking it from the block job
data.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Eric Blake <a9da18479c871fe903d9590822cfe2629c6a4d11@redhat.com>

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