[Ubuntu] get rid of post-gen rust script (#4575)

images/linux/post-generation/rust-permissions.sh

@@ -1,14 +0,0 @@
-#!/bin/bash
-
-# Fix permissions for the Rust folder
-# https://github.com/actions/virtual-environments/issues/572
-
-rust_folder="/usr/share/rust"
-rust_user=$(cut -d: -f1 /etc/passwd | tail -1)
-
-if [ -d "$rust_folder" ]; then
-    rust_folder_owner=$(ls -ld $rust_folder | awk '{print $3}')
-    if [ "$rust_user" != "$rust_folder_owner" ]; then
-        chown "$rust_user":docker -R $rust_folder
-    fi
-fi