Reverted to custom script on normal dist

Author: grimzy

.travis.yml

@@ -1,6 +1,5 @@
 language: php
 
-dist: trusty
 sudo: required
 
 php:
@@ -15,6 +14,7 @@ services:
   - mysql
 
 before_install:
+  - bash .travis.install-mysql-5.7.sh
   - mysql -e 'CREATE DATABASE test;'
 
 install: composer install