asterisk: use correct ranges with tr

The tr command does not take regular expressions and should not be
used with ranges such as [a-z] which furthermore can cause issues if
unquoted as they are interpreted by the shell.

net/asterisk/files/iopsys/lib/voice/config_asterisk.sh

@@ -1844,7 +1844,7 @@ configure_logger() {
 
 configure_indications() {
 	config_get country tel_options country
-	country_code=$(echo $country | tr [A-Z] [a-z])
+	country_code=$(echo $country | tr 'A-Z' 'a-z')
 	sed -i "s/^country=.*/country=${country_code}/g" $WORK_DIR/indications.conf
 }