Revert "Avoid a concrete dependency on PresentsServer."

This reverts commit 938847bea9.

This didn't turn out to work well enough, so let's avoid unhelpful indirection.

core/src/main/java/com/threerings/presents/server/PresentsServer.java

@@ -47,7 +47,7 @@ import static com.threerings.presents.Log.log;
  * instance is initialized.
  */
 @Singleton
-public class PresentsServer implements RebootManager.Rebootable
+public class PresentsServer
 {
     /** Configures dependencies needed by the Presents services. */
     public static class PresentsModule extends AbstractModule

core/src/main/java/com/threerings/presents/server/RebootManager.java

@@ -27,15 +27,6 @@ import static com.threerings.presents.Log.log;
  */
 public abstract class RebootManager
 {
-    /** An interface implemented by the server we're going to shut down. We do this to avoid having
-      * a dependency on PresentsServer directly because that tends to cause cyclic dependencies for
-      * the real servers (like ProjectX) that use Guice to inject dependencies. */
-    public static interface Rebootable {
-        /** Queues up a request to shutdown on the event thread. This method may be safely called
-          * from any thread. */
-        void queueShutdown ();
-    }
-
     /**
      * An interface for receiving notifications about pending automated shutdowns.
      */
@@ -172,7 +163,7 @@ public abstract class RebootManager
     /**
      * Provides us with our dependencies.
      */
-    protected RebootManager (Rebootable server, RootDObjectManager omgr)
+    protected RebootManager (PresentsServer server, RootDObjectManager omgr)
     {
         _server = server;
         _omgr = omgr;
@@ -342,7 +333,7 @@ public abstract class RebootManager
     }
 
     /** The server that we're going to reboot. */
-    protected Rebootable _server;
+    protected PresentsServer _server;
 
     /** Our distributed object manager. */
     protected RootDObjectManager _omgr;