Use fakeroot when running tests and enable user_xattr

.travis.yml

@@ -6,5 +6,7 @@ python:
 install:
   - "pip install --use-mirrors Cython"
   - "pip install -e ."
+  - "apt-get install fakeroot"
+  - "mount / -o remount,user_xattr"
 # command to run tests
-script: python -m darc.testsuite.run -vb
+script: fakeroot python -m darc.testsuite.run -vb