decorate start_directory builder test with retries

Author: tony

tests/test_workspacebuilder.py

@@ -322,6 +322,7 @@ def test_blank_pane_count(session):
     assert len(window4._panes) == 2
 
 
+@flaky(max_runs=5, min_passes=1)
 def test_start_directory(session, tmpdir):
     yaml_config = loadfixture("workspacebuilder/start_directory.yaml")
     test_dir = str(tmpdir.mkdir('foo bar'))