Remove feature io_error_more from bin

Summary: `read_to_string` does not return `NotADirectory`.

Reviewed By: ndmitchell

Differential Revision: D41092312

fbshipit-source-id: 0329db949cb38c3751ad72fe9ba935d61fe604dd

Author: stepancheg

starlark/bin/eval.rs

@@ -312,12 +312,7 @@ impl LspContext for Context {
             LspUrl::File(path) => match path.is_absolute() {
                 true => match fs::read_to_string(path) {
                     Ok(contents) => Ok(Some(contents)),
-                    Err(e)
-                        if e.kind() == io::ErrorKind::NotFound
-                            || e.kind() == io::ErrorKind::NotADirectory =>
-                    {
-                        Ok(None)
-                    }
+                    Err(e) if e.kind() == io::ErrorKind::NotFound => Ok(None),
                     Err(e) => Err(e.into()),
                 },
                 false => Err(ContextError::NotAbsolute(uri.clone()).into()),

starlark/bin/main.rs

@@ -17,7 +17,6 @@
 
 // Features we use
 #![feature(box_syntax)]
-#![feature(io_error_more)]
 //
 // Plugins
 #![cfg_attr(feature = "gazebo_lint", feature(plugin))]