Make sure we do not close the running session (#544)
Make sure we do not close the running session (#544)

We must only close the temporary session used for the request.
Fixes: 854920dfb2a2
Signed-off-by: Fatih Acar <3fd41b8e97ee00cb272ade397318b938056b45d9@criteo.com>
slackapi/python-slackclient,slackapi/python-slackclient,slackhq/python-slackclient,slackapi/python-slackclient