Simplify `branch_name` in bin/changelogrs-simplify-changelog-branch_name

The `--short` option has existed since at least 1.8.1:
https://git-scm.com/docs/git-symbolic-ref/1.8.1

1 files changed, 1 insertions, 1 deletions

diff --git a/bin/changelog b/bin/changelog
index b6586ebb6aa..e07b1ad237a 100755
--- a/bin/changelog
+++ b/bin/changelog
@@ -158,7 +158,7 @@ class ChangelogEntry
   end
 
   def branch_name
-    @branch_name ||= %x{git symbolic-ref HEAD}.strip.sub(%r{\Arefs/heads/}, '')
+    @branch_name ||= %x{git symbolic-ref --short HEAD}.strip
   end
 end