Simplify argument parsing in yt-conv.

yt-conv

@@ -26,9 +26,7 @@ if [ $# -ne 1 ]
 then
 	>&2 echo "Usage: $0 <url>"
 	exit 1
-fi
-
-if [ "$1" = "-h" ]
+elif [ "$1" = "-h" ]
 then
 	echo "Usage: $0 <url>"
 	exit 0