Fix typo!

This typo would cause the error message to be lost, which is suboptimal
diff --git a/tsqa/test_cases.py b/tsqa/test_cases.py
index b145df2..f2de20d 100644
--- a/tsqa/test_cases.py
+++ b/tsqa/test_cases.py
@@ -190,7 +190,7 @@
 
         cls.http_endpoint.ready.wait()
         if cls.http_endpoint.error is not None:
-            raise unittest.SkipTest('Error starting DynamicHTTPEndpoint: {0}'.format(e))
+            raise unittest.SkipTest('Error starting DynamicHTTPEndpoint: {0}'.format(cls.http_endpoint.error))
 
         # Do this last, so we can get our stuff registered
         # call parent constructor