mem_replace: apply update_lints tool.

CHANGELOG.md

@@ -744,6 +744,7 @@ All notable changes to this project will be documented in this file.
 [`match_wild_err_arm`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#match_wild_err_arm
 [`maybe_infinite_iter`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#maybe_infinite_iter
 [`mem_forget`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#mem_forget
+[`mem_replace_option_with_none`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#mem_replace_option_with_none
 [`min_max`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#min_max
 [`misaligned_transmute`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#misaligned_transmute
 [`misrefactored_assign_op`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#misrefactored_assign_op

README.md

@@ -9,7 +9,7 @@ We are currently in the process of discussing Clippy 1.0 via the RFC process in
 
 A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
 
-[There are 276 lints included in this crate!](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
+[There are 277 lints included in this crate!](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
 
 We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
 

clippy_lints/src/lib.rs

@@ -593,6 +593,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry<'_>, conf: &Conf) {
         matches::MATCH_REF_PATS,
         matches::MATCH_WILD_ERR_ARM,
         matches::SINGLE_MATCH,
+        mem_replace::MEM_REPLACE_OPTION_WITH_NONE,
         methods::CHARS_LAST_CMP,
         methods::CHARS_NEXT_CMP,
         methods::CLONE_DOUBLE_REF,