Update clippy settings and fix a few clippy warnings.

lib/faerie/src/backend.rs

@@ -152,8 +152,7 @@ impl Backend for FaerieBackend {
         namespace: &ModuleNamespace<Self>,
         code_size: u32,
     ) -> ModuleResult<FaerieCompiledFunction> {
-        let mut code: Vec<u8> = Vec::with_capacity(code_size as usize);
-        code.resize(code_size as usize, 0);
+        let mut code: Vec<u8> = vec![0; code_size as usize];
 
         // Non-lexical lifetimes would obviate the braces here.
         {

lib/faerie/src/lib.rs

@@ -12,7 +12,7 @@
 #![cfg_attr(feature = "clippy", plugin(clippy(conf_file = "../../clippy.toml")))]
 #![cfg_attr(
     feature = "cargo-clippy",
-    allow(new_without_default, new_without_default_derive)
+    allow(clippy::new_without_default, clippy::new_without_default_derive)
 )]
 #![cfg_attr(
     feature = "cargo-clippy",