Add distro support for KVM for IBM z Systems

Add "KVM for IBM z Systems" to the list of Fedora-like distros.

As the distribution does not have a dedicated kvm package,
prevent the installation of the kvm package during the libvirt
setup.

Change-Id: Ibb5c60797d6867264f9dea7fea85cdf1d7c72ded
diff --git a/lib/nova_plugins/functions-libvirt b/lib/nova_plugins/functions-libvirt
index dae55c6..0afdad8 100644
--- a/lib/nova_plugins/functions-libvirt
+++ b/lib/nova_plugins/functions-libvirt
@@ -38,7 +38,10 @@
         fi
         #pip_install_gr <there-si-no-guestfs-in-pypi>
     elif is_fedora || is_suse; then
-        install_package kvm
+        # On "KVM for IBM z Systems", kvm does not have its own package
+        if [[ ! ${DISTRO} =~ "kvmibm1" ]]; then
+            install_package kvm
+        fi
         # there is a dependency issue with kvm (which is really just a
         # wrapper to qemu-system-x86) that leaves some bios files out,
         # so install qemu-kvm (which shouldn't strictly be needed, as