testing: don't reset PYTHONPATH

we no longer use python setup.py test

slapos/testing/utils.py

@@ -219,8 +219,7 @@ class CrontabMixin(object):
     """
     crontab_command =  self._getCrontabCommand(crontab_name)
     crontab_output = subprocess.check_output(
-        # XXX we unset PYTHONPATH set by `setup.py test`
-        "env PYTHONPATH= faketime {date} bash -o pipefail -e -c '{crontab_command}'".format(**locals()),
+        "faketime {date} bash -o pipefail -e -c '{crontab_command}'".format(**locals()),
         shell=True,
     )
     self.logger.debug("crontab %s output: %s", crontab_command, crontab_output)