SSH: catch TimeoutError during login with a clean fail message

plaintext_login() only caught AuthenticationException and SSHException
before falling through to the generic Exception handler, which logs via
logger.exception() and dumps a full traceback. A connection timing out
mid-login is routine on a target sweep, not something that needs a stack
trace, and smb.py already treats TimeoutError this way elsewhere in the
codebase.

Fixes #358

nxc/protocols/ssh.py

@@ -134,6 +134,8 @@ class ssh(connection):
                 self.logger.error(f"Internal Paramiko error for {username}:{process_secret(password)}, {e}")
             else:
                 self.logger.exception(e)
+        except TimeoutError:
+            self.logger.fail(f"{username}:{process_secret(password)} Connection timed out")
         except Exception as e:
             self.logger.exception(e)
             self.conn.close()