Add code to enable discovery for mqtt cover (#10580)

* Add code to enable discovery for mqtt cover

* Fix pylint error

homeassistant/components/cover/mqtt.py

@@ -104,6 +104,9 @@ PLATFORM_SCHEMA = mqtt.MQTT_BASE_PLATFORM_SCHEMA.extend({
 @asyncio.coroutine
 def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
     """Set up the MQTT Cover."""
+    if discovery_info is not None:
+        config = PLATFORM_SCHEMA(discovery_info)
+
     value_template = config.get(CONF_VALUE_TEMPLATE)
     if value_template is not None:
         value_template.hass = hass

homeassistant/components/mqtt/discovery.py

@@ -20,10 +20,12 @@ TOPIC_MATCHER = re.compile(
     r'(?P<prefix_topic>\w+)/(?P<component>\w+)/'
     r'(?:(?P<node_id>[a-zA-Z0-9_-]+)/)?(?P<object_id>[a-zA-Z0-9_-]+)/config')
 
-SUPPORTED_COMPONENTS = ['binary_sensor', 'fan', 'light', 'sensor', 'switch']
+SUPPORTED_COMPONENTS = [
+    'binary_sensor', 'cover', 'fan', 'light', 'sensor', 'switch']
 
 ALLOWED_PLATFORMS = {
     'binary_sensor': ['mqtt'],
+    'cover': ['mqtt'],
     'fan': ['mqtt'],
     'light': ['mqtt', 'mqtt_json', 'mqtt_template'],
     'sensor': ['mqtt'],