blog.ezyang.com reverted to HTTP

Author: drtychai

book/src/clauses/coherence.md

@@ -19,7 +19,7 @@ To check for coherence, the Rust compiler completes two separate but related che
 - [Coherence - talk by withoutboats](https://air.mozilla.org/rust-meetup-march-2017/)
 - [Little Orphan Impls](https://smallcultfollowing.com/babysteps/blog/2015/01/14/little-orphan-impls/)
 - [RFC 1023 Rebalancing Coherence](https://rust-lang.github.io/rfcs/1023-rebalancing-coherence.html)
-- [Type classes: confluence, coherence and global uniqueness](https://blog.ezyang.com/2014/07/type-classes-confluence-coherence-global-uniqueness/)
+- [Type classes: confluence, coherence and global uniqueness](http://blog.ezyang.com/2014/07/type-classes-confluence-coherence-global-uniqueness/)
 ## Axioms & Properties of Coherence
 > Historical Note: We used to use the term “external” instead of “upstream”.