Fix NPE when restoring from Add account screen

Fixes b/6274397

Change-Id: I4434575acf4399127fb00e4d77c8f134e6429ffb
diff --git a/src/com/android/mail/ui/AbstractActivityController.java b/src/com/android/mail/ui/AbstractActivityController.java
index fa1bb42..8f5f387 100644
--- a/src/com/android/mail/ui/AbstractActivityController.java
+++ b/src/com/android/mail/ui/AbstractActivityController.java
@@ -416,7 +416,7 @@
     // TODO(mindyp): set this up to store a copy of the folder as a transient
     // field in the account.
     protected void loadAccountInbox() {
-        restartOptionalLoader(LOADER_ACCOUNT_INBOX, null);
+        restartOptionalLoader(LOADER_ACCOUNT_INBOX, Bundle.EMPTY);
     }
 
     /** Set the current folder */