data/scripts/backup: don't backup /var/log if it is not a directory

Origin commit data
------------------
Branch: ni/coolstream
Commit: c3abfa581f
Author: vanhofen <vanhofen@gmx.de>
Date: 2023-10-05 (Thu, 05 Oct 2023)

Origin message was:
------------------
- data/scripts/backup: don't backup /var/log if it is not a directory

------------------
No further description and justification available within origin commit message!

------------------
This commit was generated by Migit

data/scripts/backup.sh.in

@@ -43,7 +43,6 @@ TOBACKUP="\
 	\
 	/var/bin/ \
 	/var/keys/ \
-	/var/log/ \
 	/var/root/ \
 	/var/xupnpd/ \
 	\
@@ -72,8 +71,12 @@ TOBACKUP="\
 	@WEBTVDIR_VAR@/ \
 "
 
-SHOWINFO "backup to ${BAKF} ..."
+# add /var/log if it is a directory
+if [ -d /var/log/ ]; then
+	TOBACKUP="$TOBACKUP /var/log/"
+fi
 
+# add tobackup.conf and its content
 if [ -e "${USRF}" ]; then
 	TOBACKUP="$TOBACKUP ${USRF}"
 	while read i
@@ -81,6 +84,8 @@ if [ -e "${USRF}" ]; then
 		done < $USRF
 fi
 
+SHOWINFO "backup to ${BAKF} ..."
+
 # check existence
 RES=""
 for i in $TOBACKUP