DestinationFactory: remove @Singleton annotation

DestinationFactory is already bound as singleton in the module
and thus does not need to be the @Singleton annotation on the class.

Change-Id: I08eac697239202b01cbac64e8a1629e9499089fb
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationFactory.java b/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationFactory.java
index 09f4f4e..da7f162 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationFactory.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/DestinationFactory.java
@@ -26,9 +26,7 @@
 import com.google.inject.Inject;
 import com.google.inject.Injector;
 import com.google.inject.Provider;
-import com.google.inject.Singleton;
 
-@Singleton
 public class DestinationFactory {
   private final Injector injector;
   private final PluginUser pluginUser;