Remove 5.0.0 entry from 5.1.0 CHANGELOG [ci skip]

The entry for PR #25430 is currently present both in the CHANGELOG
for Rails 5.0 and for Rails 5.1:

https://github.com/rails/rails/blame/9d3a352777c2594123583b0bc02d0dd80f1e385b/railties/CHANGELOG.md#L61-L72

Since the PR was backported to 5-0-stable in #25499, I believe it
should be removed from the CHANGELOG of 5.1, otherwise it looks like
something changed from 5.0 to 5.1

railties/CHANGELOG.md

@@ -192,10 +192,6 @@
 
     *Kevin McPhillips*
 
-*   Ensure `/rails/info` routes match in development for apps with a catch-all globbing route.
-
-    *Nicholas Firth-McCoy*
-
 *   Added a shared section to `config/secrets.yml` that will be loaded for all environments.
 
     *DHH*