removing unused imports.

src/quirks.rs

@@ -12,8 +12,6 @@
 //! you probably want to use `Url` method instead.
 
 use parser::{default_port, Context, Input, Parser, SchemeType};
-use std::cell::RefCell;
-use SyntaxViolation;
 use {idna, Host, ParseError, Position, Url};
 
 /// https://url.spec.whatwg.org/#dom-url-domaintoascii