Update conftest to raise e in compliance with flake8.

Author: rfoliva

tests/conftest.py

@@ -54,8 +54,8 @@ def session(server):
         pass
     except exc.LibTmuxException as e:
         # server.attach_session(session.get('session_id'))
-        pass
-
+        raise e
+        
     for old_test_session in old_test_sessions:
         logger.debug('Old test test session %s found. Killing it.' % old_test_session)
         server.kill_session(old_test_session)