Delete obsolete clippy scripts.

check-clippy.sh

@@ -1,10 +0,0 @@
-#!/bin/bash
-set -euo pipefail
-
-# Usage: check-clippy.sh
-
-if cargo install --list | tee /dev/null | grep -q "^clippy v0"; then
-    exit 0
-else
-    exit 1
-fi