Remove unused and deprecated `tempdir` dependency

boring/Cargo.toml

@@ -19,6 +19,5 @@ libc = "0.2"
 boring-sys = { version = "1.1.0", path = "../boring-sys" }
 
 [dev-dependencies]
-tempdir = "0.3"
 hex = "0.4"
 rusty-hook = "^0.11"

boring/src/lib.rs

@@ -13,8 +13,6 @@ extern crate libc;
 
 #[cfg(test)]
 extern crate hex;
-#[cfg(test)]
-extern crate tempdir;
 
 #[doc(inline)]
 pub use crate::ffi::init;

boring/src/ssl/test/mod.rs

@@ -14,7 +14,6 @@ use std::process::{Child, ChildStdin, Command, Stdio};
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::thread;
 use std::time::Duration;
-use tempdir::TempDir;
 
 use crate::dh::Dh;
 use crate::error::ErrorStack;