install: leaks os error when the --sort-program not exist

Hi, uutils mainteners

to reproduce that is simple just

```css
relunsec@relunsec:~/software/coreutils/target/debug$ ./install --strip-program /root -s a b
install: strip program failed: Permission denied (os error 13)
relunsec@relunsec:~/software/coreutils/target/debug$ 
```