Silence error in log flush subroutine when no pihole-FTL.conf can be found

Signed-off-by: DL6ER <dl6er@dl6er.de>

advanced/Scripts/piholeLogFlush.sh

@@ -16,7 +16,7 @@ source ${colfile}
 # Constructed to return nothing when
 # a) the setting is not present in the config file, or
 # b) the setting is commented out (e.g. "#DBFILE=...")
-DBFILE="$(sed -n -e 's/^\s^.DBFILE\s*=\s*//p' /etc/pihole/pihole-FTL.conf)"
+DBFILE="$(sed -n -e 's/^\s^.DBFILE\s*=\s*//p' /etc/pihole/pihole-FTL.conf 2> /dev/null)"
 # Test for empty string. Use standard path in this case.
 if [ -z "$DBFILE" ]; then
   DBFILE="/etc/pihole/pihole-FTL.db"