A round of stable kernel updates

This round of kernel updates address a speculative-execution vulnerability found
in all Intel processors made since 2011. Greg Kroah-Hartman says in the 5.1.2 kernel patch: 'Note, this release,
and the other stable releases that are all being released right now at the
same time, just went out all contain patches that have only seen the
'public eye' for about 5 minutes. So be forwarned, they might break
things, they might not build, but hopefully they fix things. Odds are we
will be fixing a number of small things in this area for the next few weeks
as things shake out on real hardware and workloads.' In addition to
5.1.2, stable kernels 5.0.16, 4.19.43, 4.14.119, and 4.9.176 are available. More information may be
found in the Xen
security advisory and this new in-kernel
documentation.