ddns-scripts-cloudflare: fix shell conditional

Signed-off-by: Glen Huang <heyhgl@gmail.com>

net/ddns-scripts/files/usr/lib/ddns/update_cloudflare_com_v4.sh

@@ -134,7 +134,7 @@ else
 fi
 __PRGBASE="$__PRGBASE --header 'Content-Type: application/json' "
 
-if [ -n "$zone_id"]; then
+if [ -n "$zone_id" ]; then
 	__ZONEID="$zone_id"
 else
 	# read zone id for registered domain.TLD