Fix clippy lints

Author: Gelbpunkt

src/dist/dist.rs

@@ -377,10 +377,10 @@ impl PartialToolchainDesc {
         let env = if self.target.os.is_some() {
             self.target.env
         } else {
-            self.target.env.or_else(|| host_env)
+            self.target.env.or(host_env)
         };
-        let arch = self.target.arch.unwrap_or_else(|| host_arch);
-        let os = self.target.os.unwrap_or_else(|| host_os);
+        let arch = self.target.arch.unwrap_or(host_arch);
+        let os = self.target.os.unwrap_or(host_os);
 
         let trip = if let Some(env) = env {
             format!("{}-{}-{}", arch, os, env)