Try to entice travis into running all the tests

I don't know why zope.testrunner quits after the first layer.  I don't
want to know.  Let's try running tests exactly the same way as tox.ini.

.travis.yml

@@ -8,6 +8,7 @@ install:
     - travis_retry pip install BTrees ZConfig manuel persistent six transaction zc.lockfile zdaemon zope.interface zope.testing zope.testrunner
     - travis_retry pip install -e .
 script:
-    - zope-testrunner -j99 --test-path=src --auto-color --auto-progress
+    - zope-testrunner -u --test-path=src --auto-color --auto-progress
+    - zope-testrunner -f -j99 --test-path=src --auto-color --auto-progress
 notifications:
     email: false