in the 91.lvs event script

IF lvs has been configured, check that the ipvsadm package has also
been installed since we depend on it.
If not, log an error and return 1

(This used to be ctdb commit 506174bbc47f1176122be2e55099149e3db27d57)

ctdb/config/events.d/91.lvs

@@ -7,6 +7,12 @@ loadconfig ctdb
 [ -z "$CTDB_LVS_PUBLIC_IP" ] && exit 0
 [ -z "$CTDB_PUBLIC_INTERFACE" ] && exit 0
 
+[ -x /sbin/ipvsadm ] || {
+    echo "LVS configured but /sbin/ipvsadm is not installed."
+    exit 1
+}
+
+
 cmd="$1"
 shift