try increasing recvtimo for test_beacon

For some reason, the test only fails on Travis.

Author: bwalex

test/test_beacon.rb

@@ -84,7 +84,7 @@ def test_announce_lookup
     sleep(0.5)
     client_beacon = ZMQ::Beacon.new(beacon_port)
     client_beacon.subscribe("tcp")
-    client_beacon.pipe.rcvtimeo = 1000
+    client_beacon.pipe.rcvtimeo = 3000
     sender_address = client_beacon.pipe.recv
     client_address = client_beacon.pipe.recv
     assert_equal rep.endpoint, client_address