SSDP discovery: allow multicast TTL setting to fail

Apparently it's not supported on Windows when using IPv6.

flamenco_worker/ssdp_discover.py

@@ -60,7 +60,11 @@ def find_flamenco_manager(timeout=1, retries=5):
             sock = socket.socket(family, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
             sock.settimeout(timeout)
             sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-            sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
+            try:
+                sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 32)
+            except OSError:
+                # Not supported on Windows and AF_INET6.
+                pass
             sock.bind(('', 1901))
 
             try: