Ignore empty files in licence check

scripts/check-licence-header.sh

@@ -91,7 +91,7 @@ for FILE in $CHANGED_FILES; do
   for EXCLUDE in "${excludes[@]}"; do
     FILE=$(echo $FILE | egrep -v "$EXCLUDE")
   done
-  if [[ -n $FILE && -f $FILE ]]; then
+  if [[ -n $FILE && -f $FILE && -s $FILE ]]; then
     licenceHeaderCheck $FILE
   fi
 done