"file_is_not_sym" currently only checks for xen-syms.  Extend it to
disregard xenpolicy (XSM policy files) and files ending .config (which
are built by the Xen upstream build system in some configurations and
can therefore end up in /boot).

Rename the function accordingly, to "file_is_not_xen_garbage".

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
---
 overlay-buster/etc/grub.d/20_linux_xen | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/overlay-buster/etc/grub.d/20_linux_xen b/overlay-buster/etc/grub.d/20_linux_xen
index fb3ed82f..01dfcb57 100755
--- a/overlay-buster/etc/grub.d/20_linux_xen
+++ b/overlay-buster/etc/grub.d/20_linux_xen
@@ -167,10 +167,14 @@ if [ "x${linux_list}" = "x" ] ; then
     exit 0
 fi
 
-file_is_not_sym () {
+file_is_not_xen_garbage () {
     case "$1" in
 	*/xen-syms-*)
 	    return 1;;
+	*/xenpolicy-*)
+	    return 1;;
+	*/*.config)
+	    return 1;;
 	*)
 	    return 0;;
     esac
@@ -178,7 +182,7 @@ file_is_not_sym () {
 
 xen_list=
 for i in /boot/xen*; do
-    if grub_file_is_not_garbage "$i" && file_is_not_sym "$i" ; then xen_list="$xen_list $i" ; fi
+    if grub_file_is_not_garbage "$i" && file_is_not_xen_garbage "$i" ; then xen_list="$xen_list $i" ; fi
 done
 prepare_boot_cache=
 boot_device_id=
-- 
2.20.1