Fix access of undefined ssh._tried_sftp in raw mode (#2396)

* Fix access of undefined `ssh._tried_sftp` in `raw` mode

The attribute was never set when setting `ssh(raw=True)` which caused the code to run `ssh.__getattr__` which raised an AttributeError due to `_tried_sftp` starting with an `_` on Python 3.12.

* Document all `ssh` attributes

Author: peace-maker

pwnlib/tubes/ssh.py

@@ -544,16 +544,32 @@ class ssh(Timeout, Logger):
     #: Remote port (``int``)
     port = None
 
+    #: Remote username (``str``)
+    user = None
+
+    #: Remote password (``str``)
+    password = None
+
+    #: Remote private key (``str``)
+    key = None
+
+    #: Remote private key file (``str``)
+    keyfile = None
+
     #: Enable caching of SSH downloads (``bool``)
     cache = True
 
+    #: Enable raw mode and don't probe the environment (``bool``)
+    raw = False
+
     #: Paramiko SSHClient which backs this object
     client = None
 
     #: PID of the remote ``sshd`` process servicing this connection.
     pid = None
 
     _cwd = '.'
+    _tried_sftp = False
 
     def __init__(self, user=None, host=None, port=22, password=None, key=None,
                  keyfile=None, proxy_command=None, proxy_sock=None, level=None,