Remove unnecessary lifetime annotation

src/url_filters/util.rs

@@ -10,7 +10,7 @@ use std::borrow::Cow;
 use url::Url;
 use super::MissingQueryError;
 
-pub fn query_pair_value<'a, 'b>(url: &'a Url, key: &'b str) -> Result<Cow<'a, str>, MissingQueryError> {
+pub fn query_pair_value<'a>(url: &'a Url, key: &str) -> Result<Cow<'a, str>, MissingQueryError> {
     let (_, value) = try!(url.query_pairs()
         .find(|&(ref k, _)| k == key)
         .ok_or(MissingQueryError::new(key)));