Reduced amount of travis jobs

Refs symfony-cmf/Testing#42

Author: wouterj

.travis.yml

@@ -6,9 +6,16 @@ php:
     - 5.5
 
 env:
-  - SYMFONY_VERSION=2.2.*
   - SYMFONY_VERSION=2.3.*
-  - SYMFONY_VERSION=dev-master
+
+matrix:
+  allow_failures:
+    - env: SYMFONY_VERSION=dev-master
+  include:
+    - php: 5.5
+      env: SYMFONY_VERSION=2.2.*
+    - php: 5.5
+      env: SYMFONY_VERSION=dev-master
 
 before_script:
   - composer self-update
@@ -20,7 +27,3 @@ script: phpunit --coverage-text
 notifications:
   irc: "irc.freenode.org#symfony-cmf"
   email: "symfony-cmf-devs@googlegroups.com"
-
-matrix:
-  allow_failures:
-    - env: SYMFONY_VERSION=dev-master