Update 450_check_bootloader_files.sh

In layout/save/default/450_check_bootloader_files.sh
added bash globbing characters [] around the first letter to ensure
that with 'shopt -s nullglob' files that do not exist will not appear
so nonexistent files are not appended to CHECK_CONFIG_FILES
cf. #2796 (comment)

usr/share/rear/layout/save/default/450_check_bootloader_files.sh

@@ -7,33 +7,38 @@
 # An artificial bash array is used so that the first array element $used_bootloader is the used bootloader:
 used_bootloader=( $( cat $VAR_DIR/recovery/bootloader ) )
 
+# No quoting of the elements that are appended to the CHECK_CONFIG_FILES array together with
+# the bash globbing characters like '*' or the [] around the first letter make sure
+# that with 'shopt -s nullglob' files that do not exist will not appear
+# so nonexistent files are not appended to CHECK_CONFIG_FILES
+# cf. https://github.com/rear/rear/pull/2796#issuecomment-1117171070
 case $used_bootloader in
     (EFI|GRUB2-EFI)
         CHECK_CONFIG_FILES+=( /boot/efi/EFI/*/grub*.cfg )
         ;;
     (GRUB|GRUB2)
-        CHECK_CONFIG_FILES+=( /etc/grub.cfg /etc/grub2.cfg /boot/grub2/grub2.cfg /boot/grub/grub.cfg )
+        CHECK_CONFIG_FILES+=( /[e]tc/grub.cfg /[e]tc/grub2.cfg /[b]oot/grub2/grub2.cfg /[b]oot/grub/grub.cfg )
         ;;
     (LILO)
-        CHECK_CONFIG_FILES+=( /etc/lilo.conf )
+        CHECK_CONFIG_FILES+=( /[e]tc/lilo.conf )
         ;;
     (ELILO)
-        CHECK_CONFIG_FILES+=( /etc/elilo.conf )
+        CHECK_CONFIG_FILES+=( /[e]tc/elilo.conf )
         ;;
     (PPC)
         # PPC arch bootloader can be :
         #  - LILO : SLES < 12
         #  - YABOOT : RHEL < 7
         #  - GRUB2 : SLES >= 12, RHEL >= 7, Ubuntu and other new Linux on POWER distro.
-        CHECK_CONFIG_FILES+=( /etc/lilo.conf /etc/yaboot.conf /etc/grub.cfg /etc/grub2.cfg /boot/grub2/grub2.cfg /boot/grub/grub.cfg)
+        CHECK_CONFIG_FILES+=( /[e]tc/lilo.conf /[e]tc/yaboot.conf /[e]tc/grub.cfg /[e]tc/grub2.cfg /[b]oot/grub2/grub2.cfg /[b]oot/grub/grub.cfg)
         ;;
     (ARM|ARM-ALLWINNER)
-        CHECK_CONFIG_FILES+=( /boot/boot.scr )
+        CHECK_CONFIG_FILES+=( /[b]oot/boot.scr )
         ;;
     (ZIPL)
         # cf. https://github.com/rear/rear/issues/2137
         # s390 - for rhel, ubuntu zipl config must be exist for restore.  sles > 11 does not use zipl directly
-        CHECK_CONFIG_FILES+=( /etc/zipl.conf )
+        CHECK_CONFIG_FILES+=( /[e]tc/zipl.conf )
         ;;
     (*)
         BugError "Unknown bootloader ($used_bootloader) - ask for sponsoring to get this fixed"