[ticket/11324] Add PHP 5.5 environment to travis and allow it to fail.

PHPBB3-11324

.travis.yml

@@ -4,11 +4,16 @@ php:
   - 5.3.3
   - 5.3
   - 5.4
+  - 5.5
 
 env:
   - DB=mysql
   - DB=postgres
 
+matrix:
+  allow_failures:
+    - php: 5.5
+
 before_script:
   - sh -c "if [ '$DB' = 'postgres' ]; then psql -c 'DROP DATABASE IF EXISTS phpbb_tests;' -U postgres; fi"
   - sh -c "if [ '$DB' = 'postgres' ]; then psql -c 'create database phpbb_tests;' -U postgres; fi"