DHT22 sensor component can't update

[langestefan]

Home Assistant release with the issue:

0.81.2

Last working Home Assistant release (if known):
I've had this issue for as long as I can remember.

Operating environment (Hass.io/Docker/Windows/etc.):

Hass.io running on a RPI3B+

Component/platform:

https://www.home-assistant.io/components/sensor.dht/

Description of problem:
Hass.io fails updating the dht sensor component.

In /Adafruit_DHT/common.py I see the following lines:

def get_platform():
    """Return a DHT platform interface for the currently detected platform."""
    plat = platform_detect.platform_detect()
    if plat == platform_detect.RASPBERRY_PI:
        # Check for version 1 or 2 of the pi.
        version = platform_detect.pi_version()
        if version == 1:
            from . import Raspberry_Pi
            return Raspberry_Pi
        elif version == 2:
            from . import Raspberry_Pi_2
            return Raspberry_Pi_2
        elif version == 3:
            """Use Pi 2 driver even though running on Pi 3"""
            from . import Raspberry_Pi_2
            return Raspberry_Pi_2
        else:
            raise RuntimeError('No driver for detected Raspberry Pi version available!')
    elif plat == platform_detect.BEAGLEBONE_BLACK:
        from . import Beaglebone_Black
        return Beaglebone_Black
    else:
        raise RuntimeError('Unknown platform.')

So I guess it has something to do with it not being able to detect my pi version.

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

sensor:
  - platform: dht
    sensor: DHT22
    pin: 4
    temperature_offset: 2.1
    humidity_offset: -3.2
    monitored_conditions:
      - temperature
      - humidity

Traceback (if applicable):

Log Details (ERROR)
Thu Nov 01 2018 22:28:21 GMT+0100 (Midden-Europese standaardtijd)

dht: Error on device update!
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/homeassistant/helpers/entity_platform.py", line 251, in _async_add_entity
    await entity.async_device_update(warning=False)
  File "/usr/local/lib/python3.6/site-packages/homeassistant/helpers/entity.py", line 349, in async_device_update
    await self.hass.async_add_executor_job(self.update)
  File "/usr/local/lib/python3.6/concurrent/futures/thread.py", line 56, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/local/lib/python3.6/site-packages/homeassistant/components/sensor/dht.py", line 121, in update
    self.dht_client.update()
  File "/usr/local/lib/python3.6/site-packages/homeassistant/util/__init__.py", line 324, in wrapper
    result = method(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/homeassistant/components/sensor/dht.py", line 156, in update
    self.sensor, self.pin)
  File "/usr/local/lib/python3.6/site-packages/Adafruit_DHT/common.py", line 94, in read_retry
    humidity, temperature = read(sensor, pin, platform)
  File "/usr/local/lib/python3.6/site-packages/Adafruit_DHT/common.py", line 80, in read
    platform = get_platform()
  File "/usr/local/lib/python3.6/site-packages/Adafruit_DHT/common.py", line 63, in get_platform
    raise RuntimeError('Unknown platform.')
RuntimeError: Unknown platform.

Additional information:
Issue was raised here but no solution was given: #15847

[fabaff]

Duplicate of #15847