Centralize all output handling into the output function

To simplify the logging in general let's completely drop any log_file
functionality and simply require a single standard output_function
for all purposes. If users would like to stream the data or log it
into a file, they will provide a log function as an output_function
that implements this similarly to the way Avocado VT did. In this
way there also won't be confusion of whether to use a log file or
a function or both and there will only be one uniform approach to
session logging.

Signed-off-by: Plamen Dimitrov <plamen.dimitrov@intra2net.com>

aexpect/client.py

@@ -127,8 +127,6 @@ def __init__(self, command=None, a_id=None, auto_close=False, echo=False,
                 locale.getpreferredencoding())
         """
         self.a_id = a_id or data_factory.generate_random_string(8)
-        self.log_file = None
-        self.log_file_fd = None
         self.closed = False
         if encoding is None:
             self.encoding = locale.getpreferredencoding()
@@ -527,7 +525,6 @@ def __init__(self, command=None, a_id=None, auto_close=False, echo=False,
         # Add a reader and a close hook
         self._add_reader("tail")
         self._add_close_hook(Tail._join_thread)
-        self._add_close_hook(Tail._close_log_file)
 
         # Init the superclass
         super().__init__(command, a_id, auto_close, echo, linesep,
@@ -610,21 +607,6 @@ def set_output_prefix(self, output_prefix):
         """
         self.output_prefix = output_prefix
 
-    def set_log_file(self, filepath, open_fd=False):
-        """
-        Set a log file name for this tail instance.
-
-        :param filepath: complete file name and path of the log.
-        :param open_fd: whether to also open the log file
-        """
-        self.log_file = filepath
-        if open_fd:
-            self.log_file_fd = open(filepath, encoding="utf-8")  # pylint: disable=R1732
-
-    def _close_log_file(self):
-        if self.log_file_fd is not None:
-            self.log_file_fd.close()
-
     def _tail(self):  # speed optimization pylint: disable=too-many-branches,too-many-statements
 
         def _print_line(text):

aexpect/remote.py

@@ -421,7 +421,6 @@ def remote_login(client, host, port, username, password, prompt, linesep="\n",
                             prompt=prompt, status_test_command=status_test_command,
                             client=client, host=host, port=port,
                             username=username, password=password)
-    session.set_log_file(log_filename)
     try:
         handle_prompts(session, username, password, prompt, timeout)
     except Exception: