sshdriver: Cleanup after process exits

Cleanup of the temporary directory should not occur until after SSH has
exited, as SSH will delete the control socket which can race with the
shutil.rmtree() and result in strange errors like:

    tools/labgrid/venv/lib/python3.10/site-packages/labgrid/environment.py:65: in cleanup
        self.targets[target].cleanup()
    tools/labgrid/venv/lib/python3.10/site-packages/labgrid/target.py:555: in cleanup
        self.deactivate_all_drivers()
    tools/labgrid/venv/lib/python3.10/site-packages/labgrid/target.py:505: in deactivate_all_drivers
        self.deactivate(drv)
    tools/labgrid/venv/lib/python3.10/site-packages/labgrid/target.py:498: in deactivate
        client.on_deactivate()
    tools/labgrid/venv/lib/python3.10/site-packages/labgrid/driver/sshdriver.py:65: in on_deactivate
        self._cleanup_own_master()
    tools/labgrid/venv/lib/python3.10/site-packages/labgrid/driver/sshdriver.py:483: in _cleanup_own_master
        shutil.rmtree(self.tmpdir)
    /usr/lib/python3.10/shutil.py:724: in rmtree
        _rmtree_safe_fd(fd, path, onerror)
    /usr/lib/python3.10/shutil.py:680: in _rmtree_safe_fd
        onerror(os.unlink, fullname, sys.exc_info())

    ...

    FileNotFoundError: [Errno 2] No such file or directory: 'control-172.16.6.0%enx5c857e32b0e4'

Also ignore errors while running shutil.rmtree() since it a best effort
cleanup

Signed-off-by: Joshua Watt <Joshua.Watt@garmin.com>
(cherry picked from commit 937217b)

Author: JoshuaWatt

labgrid/driver/sshdriver.py

@@ -480,10 +480,11 @@ def _cleanup_own_master(self):
 
         if res != 0:
             self.logger.info("Socket already closed")
-        shutil.rmtree(self.tmpdir)
 
         self.process.communicate()
 
+        shutil.rmtree(self.tmpdir, ignore_errors=True)
+
     def _start_keepalive(self):
         """Starts a keepalive connection via the own or external master."""
         args = ["ssh", *self.ssh_prefix, self.networkservice.address, "cat"]