Close test log handler at end of test to fix file descriptor leak

zipline/utils/test_utils.py

@@ -15,6 +15,7 @@ def setup_logger(test, path='/var/log/zipline/zipline.log'):
 
 def teardown_logger(test):
     test.log_handler.pop_application()
+    test.log_handler.close()
 
 def check_list(test, a, b, label):
     test.assertTrue(isinstance(a, (list, blist.blist)))