Add port parameter to ssh Client

This commit adds a port parameter to the ssh.Client. We don't use it in
our test cases. However, it would be good to have it when I debug this
class because my development host ssh port is not 22. And I think
that it is natural a ssh client has this feature.

Change-Id: Id8b73108f67fe8c581dd8fba90902869b4ee776d
diff --git a/releasenotes/notes/add-ssh-port-parameter-to-client-6d16c374ac4456c1.yaml b/releasenotes/notes/add-ssh-port-parameter-to-client-6d16c374ac4456c1.yaml
new file mode 100644
index 0000000..b2ad199
--- /dev/null
+++ b/releasenotes/notes/add-ssh-port-parameter-to-client-6d16c374ac4456c1.yaml
@@ -0,0 +1,4 @@
+---
+features:
+  - A new optional parameter `port` for ssh client (`tempest.lib.common.ssh.Client`)
+    to specify destination port for a host. The default value is 22.
diff --git a/tempest/lib/common/ssh.py b/tempest/lib/common/ssh.py
index a831dbd..9002a45 100644
--- a/tempest/lib/common/ssh.py
+++ b/tempest/lib/common/ssh.py
@@ -36,9 +36,11 @@
 class Client(object):
 
     def __init__(self, host, username, password=None, timeout=300, pkey=None,
-                 channel_timeout=10, look_for_keys=False, key_filename=None):
+                 channel_timeout=10, look_for_keys=False, key_filename=None,
+                 port=22):
         self.host = host
         self.username = username
+        self.port = port
         self.password = password
         if isinstance(pkey, six.string_types):
             pkey = paramiko.RSAKey.from_private_key(
@@ -58,17 +60,17 @@
             paramiko.AutoAddPolicy())
         _start_time = time.time()
         if self.pkey is not None:
-            LOG.info("Creating ssh connection to '%s' as '%s'"
+            LOG.info("Creating ssh connection to '%s:%d' as '%s'"
                      " with public key authentication",
-                     self.host, self.username)
+                     self.host, self.port, self.username)
         else:
-            LOG.info("Creating ssh connection to '%s' as '%s'"
+            LOG.info("Creating ssh connection to '%s:%d' as '%s'"
                      " with password %s",
-                     self.host, self.username, str(self.password))
+                     self.host, self.port, self.username, str(self.password))
         attempts = 0
         while True:
             try:
-                ssh.connect(self.host, username=self.username,
+                ssh.connect(self.host, port=self.port, username=self.username,
                             password=self.password,
                             look_for_keys=self.look_for_keys,
                             key_filename=self.key_filename,
diff --git a/tempest/tests/lib/test_ssh.py b/tempest/tests/lib/test_ssh.py
index b07f6bc..8a0a84c 100644
--- a/tempest/tests/lib/test_ssh.py
+++ b/tempest/tests/lib/test_ssh.py
@@ -69,6 +69,7 @@
             mock.sentinel.aa)
         expected_connect = [mock.call(
             'localhost',
+            port=22,
             username='root',
             pkey=None,
             key_filename=None,