Make rushlink --delete work with urls that have a file extension.

contrib/rushlink

@@ -31,6 +31,9 @@ del() {
             URL="$LINK$1"
             ;;
     esac
+    # Remove file extension, if any.
+    NAME="${URL##*/}"
+    URL="${URL%/*}/${NAME%%.*}"
     if DELURL=$(grep -s -m1 "$URL?deleteToken=" "$DELFILE"); then
         echo "Deleting $URL..." >&2
         curl -sS -X DELETE "$DELURL" | grep deleted