Revert "Update WordPress version"

This reverts commit fe002cd.

Author: keesiemeijer

.travis.yml

@@ -15,7 +15,7 @@ before_install:
     # Setup WP_TESTS_DIR (needed to bootstrap WP PHPUnit tests). 
     - export WP_TESTS_DIR=/tmp/wordpress/tests/phpunit/
     # Clone the WordPress develop repo.
-    - git clone --depth=1 --branch="4.9" git://develop.git.wordpress.org/ /tmp/wordpress/
+    - git clone --depth=1 --branch="4.3" git://develop.git.wordpress.org/ /tmp/wordpress/
     # Setup DB.
     - mysql -e "CREATE DATABASE wordpress_test;" -uroot
     # Setup wp-config.