Remove unneeded .clone() call

`pattern` is a reference, and according to `cargo test` output: "the
type `[u8]` does not implement `Clone`, so calling `clone` on `&[u8]`
copies the reference, which does not do anything and can be removed".

src/smack/smack.rs

@@ -61,7 +61,7 @@ pub struct Smack {
 }
 
 fn make_copy_of_pattern(pattern: &[u8], is_nocase: bool) -> Vec<u8> {
-    let mut p = pattern.clone().to_vec();
+    let mut p = pattern.to_vec();
     for i in 0..p.len() {
         if is_nocase {
             p[i] = p[i].to_ascii_lowercase();