Frameworks base: Promote dream setting defaults to config.

So that:
 - the values can be shared (to fix assoc bug)
 - the values can be customized in product overlays

Bug:7373284
Change-Id: I37f037082523a3d975f6014f36afa28c60117372
diff --git a/services/java/com/android/server/SystemServer.java b/services/java/com/android/server/SystemServer.java
index eaaf33f..e46afd3 100644
--- a/services/java/com/android/server/SystemServer.java
+++ b/services/java/com/android/server/SystemServer.java
@@ -737,7 +737,7 @@
             }
             
             if (context.getResources().getBoolean(
-                    com.android.internal.R.bool.config_enableDreams)) {
+                    com.android.internal.R.bool.config_dreamsSupported)) {
                 try {
                     Slog.i(TAG, "Dreams Service");
                     // Dreams (interactive idle-time views, a/k/a screen savers)