Make TAG used for logging in StaggeredGridLayoutManager private.

The tag prevents developers that are extending SGLM to create
their own constant TAG. Additionally, it will stop from autocompleting
TAG in the IDE as well.

Bug:
https://code.google.com/p/android/issues/detail?id=213269

Change-Id: Ie817ab2a5858632d17f3a3c886f992c1d0635f05
diff --git a/api/current.txt b/api/current.txt
index 8ad450d..c76d65b 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -9927,7 +9927,6 @@
     field public static final int GAP_HANDLING_MOVE_ITEMS_BETWEEN_SPANS = 2; // 0x2
     field public static final int GAP_HANDLING_NONE = 0; // 0x0
     field public static final int HORIZONTAL = 0; // 0x0
-    field public static final java.lang.String TAG = "StaggeredGridLayoutManager";
     field public static final int VERTICAL = 1; // 0x1
   }
 
diff --git a/v7/recyclerview/src/android/support/v7/widget/StaggeredGridLayoutManager.java b/v7/recyclerview/src/android/support/v7/widget/StaggeredGridLayoutManager.java
index 9207caa..67780a8 100644
--- a/v7/recyclerview/src/android/support/v7/widget/StaggeredGridLayoutManager.java
+++ b/v7/recyclerview/src/android/support/v7/widget/StaggeredGridLayoutManager.java
@@ -54,7 +54,7 @@
  */
 public class StaggeredGridLayoutManager extends RecyclerView.LayoutManager {
 
-    public static final String TAG = "StaggeredGridLayoutManager";
+    private static final String TAG = "StaggeredGridLayoutManager";
 
     private static final boolean DEBUG = false;