Fix eventsource require

Dan Richelson · Dan Richelson · commit 7b61ed680e2c · 2017-01-31T14:00:58.000-08:00
diff --git a/lib/ldclient-rb/stream.rb b/lib/ldclient-rb/stream.rb
@@ -1,6 +1,6 @@
 require "concurrent/atomics"
 require "json"
-require "ld_celluloid_eventsource/eventsource"
+require "celluloid/eventsource"
 
 module LaunchDarkly
   PUT = :put
