xen soname bump with 4.19.0 release

[Michael Young]

I have built an update of xen to the 4.19.0 release on rawhide in the 
f41-build-side-93515 side tag. I believe that the qemu, libvirt and 
collectd packages will need to be rebuilt in this side tag due to the 
version change on some of the xen libraries.

Michael Young