Add trusty to make python2.6 available

.travis.yml

@@ -3,6 +3,7 @@ language: python
 matrix:
   include:
     - python: 2.6
+      dist: trusty
       # If the role contains python code that should be linted and tested, say
       # this by setting LSR_USE_PYTHON environment variable to the value that
       # evaluates as true in the role's repository settings page at