AvatarTask: Fix NPE, handle null bitmap

Change-Id: I209efa059c98e74a634bd309ce63f62969e11bec
Signed-off-by: Edwin Kempin <ekempin@google.com>
diff --git a/app/src/main/java/com/google/reviewit/AvatarTask.java b/app/src/main/java/com/google/reviewit/AvatarTask.java
index f47d305..601dab1 100644
--- a/app/src/main/java/com/google/reviewit/AvatarTask.java
+++ b/app/src/main/java/com/google/reviewit/AvatarTask.java
@@ -85,7 +85,7 @@
       }
     }
     Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
-    return getRoundedCornerBitmap(bitmap, 10);
+    return bitmap != null ? getRoundedCornerBitmap(bitmap, 10) : null;
   }
 
   protected void postExecute(Bitmap result) {