change symfony version in travis

.travis.yml

@@ -2,9 +2,9 @@ language: php
 php:
   - 5.3
   # - 5.4
-  
+
 env:
-  - SYMFONY_VERSION=v2.0.5	
+  - SYMFONY_VERSION=v2.0.6
   - SYMFONY_VERSION=origin/master
 
 before_script: php Tests/tests/vendors.php