use Ubuntu Precise for PHP 5.4 and 5.5 too

Author: xabbuh

.travis.yml

@@ -7,8 +7,6 @@ cache:
     - $HOME/.composer/cache/files
 
 php:
-  - 5.4
-  - 5.5
   - 5.6
   - 7.0
   - 7.1
@@ -19,6 +17,10 @@ matrix:
     - php: 5.3
       dist: precise
       env: COMPOSER_OPTIONS="--prefer-lowest --prefer-stable"
+    - php: 5.4
+      dist: precise
+    - php: 5.5
+      dist: precise
     - php: 7.2
       env: deps="high"