Fix NPE on failed loader queries.

Bug: 9901236
Change-Id: I3139174dd03ac3e79960f03729b7a39528804d76
diff --git a/src/com/android/launcher3/LauncherModel.java b/src/com/android/launcher3/LauncherModel.java
index 28530e6..eaa2fd2 100644
--- a/src/com/android/launcher3/LauncherModel.java
+++ b/src/com/android/launcher3/LauncherModel.java
@@ -1728,7 +1728,9 @@
                         }
                     }
                 } finally {
-                    c.close();
+                    if (c != null) {
+                        c.close();
+                    }
                 }
 
                 if (itemsToRemove.size() > 0) {