Squeezebox Fix duplicate server from discovery (#12063)

* Fix duplicate server from discovery

* Use hass.data instead of global

* Simplify

homeassistant/components/media_player/squeezebox.py

@@ -47,6 +47,8 @@ SERVICE_CALL_METHOD = 'squeezebox_call_method'
 
 DATA_SQUEEZEBOX = 'squeezebox'
 
+KNOWN_SERVERS = 'squeezebox_known_servers'
+
 ATTR_PARAMETERS = 'parameters'
 
 SQUEEZEBOX_CALL_METHOD_SCHEMA = MEDIA_PLAYER_SCHEMA.extend({
@@ -67,6 +69,10 @@ def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
     """Set up the squeezebox platform."""
     import socket
 
+    known_servers = hass.data.get(KNOWN_SERVERS)
+    if known_servers is None:
+        hass.data[KNOWN_SERVERS] = known_servers = set()
+
     if DATA_SQUEEZEBOX not in hass.data:
         hass.data[DATA_SQUEEZEBOX] = []
 
@@ -92,6 +98,10 @@ def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
             "Could not communicate with %s:%d: %s", host, port, error)
         return False
 
+    if ipaddr in known_servers:
+        return
+
+    known_servers.add(ipaddr)
     _LOGGER.debug("Creating LMS object for %s", ipaddr)
     lms = LogitechMediaServer(hass, host, port, username, password)