Fix inconrrect variable dereference in update-changelog.sh

Author: yrodiere

update-changelog.sh

@@ -116,4 +116,4 @@ trap "rm -f $changelog_update_file" EXIT
 create_changelog_update > "$changelog_update_file"
 sed -i "3r$changelog_update_file" "$CHANGELOG"
 git add "$CHANGELOG"
-git commit -m "[Jenkins release job] changelog.txt updated by release build #{RELEASE_VERSION}"
+git commit -m "[Jenkins release job] changelog.txt updated by release build ${RELEASE_VERSION}"