xenopsd: fix Xen version comparison. 4.17 is > 4.2, not lower!

Don't use string comparisons for versions, "17" < "2", but 17 > 2!

Signed-off-by: Edwin Török <[email protected]>

ocaml/xenopsd/xc/xenops_server_xen.ml

@@ -5146,12 +5146,13 @@ let look_for_xenctrl () =
 let init () =
   look_for_forkexec () ;
   let major, minor = look_for_xen () in
+  let major = int_of_string major and minor = int_of_string minor in
   look_for_xenctrl () ;
   if
-    major < "4" || ((major = "4" && minor < "2") && !Xenopsd.run_hotplug_scripts)
+    major < 4 || ((major = 4 && minor < 2) && !Xenopsd.run_hotplug_scripts)
   then (
     error
-      "This is xen version %s.%s. On all versions < 4.1 we must use \
+      "This is xen version %d.%d. On all versions < 4.1 we must use \
        hotplug/udev scripts"
       major minor ;
     error