Allowing for the missing of a directory during cleanup to not be a hard error

Author: x46085

src/librustc_incremental/persist/fs.rs

@@ -927,7 +927,10 @@ fn all_except_most_recent(
 fn safe_remove_dir_all(p: &Path) -> io::Result<()> {
     if p.exists() {
         let canonicalized = p.canonicalize()?;
-        std_fs::remove_dir_all(canonicalized)
+        match std_fs::remove_dir_all(canonicalized) {
+            Err(ref err) if err.kind() == io::ErrorKind::NotFound => Ok(()),
+            result => result,
+        }
     } else {
         Ok(())
     }