Fixes warning about session reuse. (#3613)

Author: zooba

azure-batch/azure/batch/batch_auth.py

@@ -116,10 +116,10 @@ def __init__(self, account_name, key):
         super(SharedKeyCredentials, self).__init__()
         self.auth = SharedKeyAuth(self.header, account_name, key)
 
-    def signed_session(self):
+    def signed_session(self, session=None):
 
-        session = super(SharedKeyCredentials, self).signed_session()
+        session = super(SharedKeyCredentials, self).signed_session(session=session)
         session.auth = self.auth
 
         return session
-    
+