Fixed build matrix

Author: kroman0

.travis.yml

@@ -7,11 +7,13 @@ env:
   - PLONE=4.1
   - PLONE=4.2
 matrix:
-  exclude:
-    - python: 2.7
+  include:
+    - python: 2.6
       env: PLONE=4.0
-    - python: 2.7
+    - python: 2.6
       env: PLONE=4.1
+    - python: 2.7
+      env: PLONE=4.2
 before_install:
   - pip install http://effbot.org/downloads/Imaging-1.1.6.tar.gz
   - sudo apt-get install -qq libxml2-dev libxslt-dev