image-update: fail upgrades if there is a local storage domain on /

Local storage should be on a separate filesystem. If it's on /
(/data, for example, without an LV), bomb out inside %pre and warn
users.

Change-Id: I5516eafabe497222b377b05bfc96056395391035
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1549630
Signed-off-by: Ryan Barry <rbarry@redhat.com>

packaging/ovirt-node-ng.spec.in

@@ -102,6 +102,19 @@ install -Dm 0755 scripts/nodectl-run-banner.sh %{buildroot}%{_sysconfdir}/profil
 /usr/bin/install -m 644 %{SOURCE1} %{buildroot}/%{_node_image_file}
 /usr/bin/install -m 644 %{SOURCE2} %{buildroot}/%{_node_image_dir}/product.img
 
+%pre image-update
+local_sds=($(find / -xdev -name "__DIRECT_IO_TEST__"))
+
+if [ "$local_sds" ]; then
+    echo "Local storage domains were found on the same filesystem as / ! Please migrate the data to a new LV before upgrading, or you will lose the VMs"
+    echo "See: https://bugzilla.redhat.com/show_bug.cgi?id=1550205#c3"
+    echo "Storage domains were found in:"
+    for sd in "${local_sds[@]}"; do
+        echo -e "\t$(dirname $sd)"
+    done
+    exit 1
+fi
+
 %post image-update
 set -e
 # Some magic to ensure that imgbase from