tempest: Obey ssh_timeout config option

The patch creates a new in-tree class that overrides default value for
tempest ssh.Client to the one defined by ssh_timeout config option.

Change-Id: I418519866e3cbd486fe0ffec23e1553ea0891420
diff --git a/neutron/tests/tempest/scenario/test_floatingip.py b/neutron/tests/tempest/scenario/test_floatingip.py
index 06f495d..d4ad72a 100644
--- a/neutron/tests/tempest/scenario/test_floatingip.py
+++ b/neutron/tests/tempest/scenario/test_floatingip.py
@@ -15,12 +15,12 @@
 
 import netaddr
 from tempest.common import waiters
-from tempest.lib.common import ssh
 from tempest.lib.common.utils import data_utils
 from tempest.lib import decorators
 from tempest import test
 import testscenarios
 
+from neutron.tests.tempest.common import ssh
 from neutron.tests.tempest import config
 from neutron.tests.tempest.scenario import base
 from neutron.tests.tempest.scenario import constants