TelnetConnction: splitting from SshConnection

Perviously, a parameter passed into SshConnection controlled whether the
connection was established over SSH or Telnet. Now, there is a separate
class for Telnet connections.

devlib/__init__.py

@@ -19,4 +19,4 @@ from devlib.trace.ftrace import FtraceCollector
 
 from devlib.host import LocalConnection
 from devlib.utils.android import AdbConnection
-from devlib.utils.ssh import SshConnection
+from devlib.utils.ssh import SshConnection, TelnetConnection

devlib/utils/ssh.py

@@ -50,7 +50,7 @@ def ssh_get_shell(host, username, password=None, keyfile=None, port=None, timeou
         if telnet:
             if keyfile:
                 raise ValueError('keyfile may not be used with a telnet connection.')
-            conn = TelnetConnection(original_prompt=original_prompt)
+            conn = TelnetPxssh(original_prompt=original_prompt)
         else:  # ssh
             conn = pxssh.pxssh()
 
@@ -74,11 +74,11 @@ def ssh_get_shell(host, username, password=None, keyfile=None, port=None, timeou
     return conn
 
 
-class TelnetConnection(pxssh.pxssh):
+class TelnetPxssh(pxssh.pxssh):
     # pylint: disable=arguments-differ
 
     def __init__(self, original_prompt):
-        super(TelnetConnection, self).__init__()
+        super(TelnetPxssh, self).__init__()
         self.original_prompt = original_prompt or r'[#$]'
 
     def login(self, server, username, password='', login_timeout=10,
@@ -165,7 +165,7 @@ class SshConnection(object):
         self.password_prompt = password_prompt if password_prompt is not None else self.default_password_prompt
         logger.debug('Logging in {}@{}'.format(username, host))
         timeout = timeout if timeout is not None else self.default_timeout
-        self.conn = ssh_get_shell(host, username, password, self.keyfile, port, timeout, telnet, original_prompt)
+        self.conn = ssh_get_shell(host, username, password, self.keyfile, port, timeout, False, None)
 
     def push(self, source, dest, timeout=30):
         dest = '{}@{}:{}'.format(self.username, self.host, dest)
@@ -276,6 +276,29 @@ class SshConnection(object):
             raise TimeoutError(e.command.replace(pass_string, ''), e.output)
 
 
+class TelnetConnection(SshConnection):
+
+    def __init__(self,
+                 host,
+                 username,
+                 password=None,
+                 port=None,
+                 timeout=None,
+                 password_prompt=None,
+                 original_prompt=None,
+                 ):
+        self.host = host
+        self.username = username
+        self.password = password
+        self.port = port
+        self.keyfile = None
+        self.lock = threading.Lock()
+        self.password_prompt = password_prompt if password_prompt is not None else self.default_password_prompt
+        logger.debug('Logging in {}@{}'.format(username, host))
+        timeout = timeout if timeout is not None else self.default_timeout
+        self.conn = ssh_get_shell(host, username, password, None, port, timeout, True, original_prompt)
+
+
 def _give_password(password, command):
     if not sshpass:
         raise HostError('Must have sshpass installed on the host in order to use password-based auth.')