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/stack.sh b/stack.sh
index 90481e0..1fa506c 100755
--- a/stack.sh
+++ b/stack.sh
@@ -183,7 +183,7 @@
 
 # Warn users who aren't on an explicitly supported distro, but allow them to
 # override check and attempt installation with ``FORCE=yes ./stack``
-if [[ ! ${DISTRO} =~ (trusty|vivid|wily|7.0|wheezy|sid|testing|jessie|f22|f23|rhel7) ]]; then
+if [[ ! ${DISTRO} =~ (trusty|vivid|wily|7.0|wheezy|sid|testing|jessie|f22|f23|rhel7|kvmibm1) ]]; then
     echo "WARNING: this script has not been tested on $DISTRO"
     if [[ "$FORCE" != "yes" ]]; then
         die $LINENO "If you wish to run this script anyway run with FORCE=yes"