[2017][rust] delete .rustfmt temp file

2017/rust/src/.day_04.rs.rustfmt

@@ -1,29 +0,0 @@
-use std::collections::HashSet;
-use failure::Error;
-
-pub fn solve(input: &str) -> Result<String, Error> {
-    Ok(input
-        .trim()
-        .lines()
-        .map(|line| Passphrase { words: line.into() })
-        .filter(Passphrase::is_valid)
-        .count()
-        .to_string())
-}
-
-struct Passphrase {
-    words: String,
-}
-
-impl Passphrase {
-    fn is_valid(&self) -> bool {
-        let mut words = HashSet::new();
-        return !self.words.split_whitespace().any(|word| {
-            if words.contains(word) {
-                return true;
-            }
-            words.insert(word);
-            return false;
-        })
-    }
-}