Update 998_dump_variables.sh

In init/default/998_dump_variables.sh
give a hint that secrets are skipped, cf.
#2967 (comment)

usr/share/rear/init/default/998_dump_variables.sh

@@ -8,4 +8,4 @@ test "$DEBUGSCRIPTS" || return 0
 # Suppress output that contains 'pass' or 'key' or 'crypt' (ignore case) to skip output
 # e.g. for BACKUP_PROG_CRYPT_KEY or SSH_ROOT_PASSWORD or LUKS_CRYPTSETUP_OPTIONS
 # cf. https://github.com/rear/rear/issues/2967
-Debug "Runtime Configuration:$LF$( declare -p | egrep -vi 'pass|key|crypt' )"
+Debug "Runtime Configuration (except what contains 'pass' or 'key' or 'crypt'):$LF$( declare -p | egrep -vi 'pass|key|crypt' )"