Poezio version: 16fee413 (or !48 (merged) maybe? I also run this)
Slixmpp version: slixmpp@c3fbc6cb

Steps to reproduce

• ???
• /close (or other actions that require finding the tab object)

Logs

2020-05-01 20:42:06,625 DEBUG:core:Got from keyboard: (['^M'],)
2020-05-01 20:42:06,625 DEBUG:inputs:Refresh: MessageInput
2020-05-01 20:42:06,626 ERROR:base_events:Exception in callback Core.on_input_readable()
handle: <Handle Core.on_input_readable()>
Traceback (most recent call last):
  File "/usr/lib/python3.8/asyncio/events.py", line 81, in _run
    self._context.run(self._callback, *self._args)
  File "/usr/lib/python3.8/site-packages/poezio/core/core.py", line 625, in on_input_readable
    self.do_command(replace_line_breaks(char), False)
  File "/usr/lib/python3.8/site-packages/poezio/core/core.py", line 784, in do_command
    self.tabs.current_tab.on_input(key, raw)
  File "/usr/lib/python3.8/site-packages/poezio/tabs/conversationtab.py", line 297, in on_input
    self.key_func[key]()
  File "/usr/lib/python3.8/site-packages/poezio/tabs/basetabs.py", line 626, in on_enter
    if not self.execute_command(txt):
  File "/usr/lib/python3.8/site-packages/poezio/tabs/basetabs.py", line 324, in execute_command
    func(arg)
  File "/usr/lib/python3.8/site-packages/poezio_plugins/alias.py", line 205, in wrapper
    return func(command, extra_args, *args, **kwargs)
  File "/usr/lib/python3.8/site-packages/poezio_plugins/alias.py", line 198, in generic_command
    return command()(new_extra_args)
  File "/usr/lib/python3.8/site-packages/poezio/decorators.py", line 81, in wrap
    return func(self, *a, **kw)
  File "/usr/lib/python3.8/site-packages/poezio/tabs/basetabs.py", line 1059, in command_unquery
    self.core.close_tab(self)
  File "/usr/lib/python3.8/site-packages/poezio/core/core.py", line 1309, in close_tab
    self.tabs.delete(tab, gap=config.get('create_gaps'))
  File "/usr/lib/python3.8/site-packages/poezio/core/tabs.py", line 239, in delete
    del self._tab_names[tab.name]
KeyError: 'irc.oftc.net'