Add test documentation for docs tox target

Enable sphinx to generate documentation from docstrings by running
'tox -e docs'.

Change-Id: I5996e5f07493f69f14172b4bb0535852e89d5456
diff --git a/neutron_tempest_plugin/common/ssh.py b/neutron_tempest_plugin/common/ssh.py
index 4cb1474..700d21b 100644
--- a/neutron_tempest_plugin/common/ssh.py
+++ b/neutron_tempest_plugin/common/ssh.py
@@ -133,7 +133,7 @@
         :returns: paramiko.Client connected to remote server.
 
         :raises tempest.lib.exceptions.SSHTimeout: in case it fails to connect
-        to remote server.
+           to remote server.
         """
         return super(Client, self)._get_ssh_connection(*args, **kwargs)