Fix race condition in Exchange account creation

* Now that observer code has been moved to worker threads, the order
  in which various pieces of account creation are executed has become
  indeterminate
* Because of this, our EasAccountsUpdatedListener could use a stale
  list of EmailProvider accounts when performing reconciliation with
  the AccountManager's list of accounts
* The fix is to ensure that EasAccountsUpdatedListener's worker thread
  causes the cached EmailProvider account list to be updated before
  calling the reconciliation method

Bug: 2558317
Change-Id: Ia94a8301845cf6c06f8efecd408eb237474f781a

src/com/android/exchange/SyncManager.java

@@ -924,7 +924,9 @@ public class SyncManager extends Service implements Runnable {
                     if (syncManager != null) {
                         android.accounts.Account[] accountMgrList = AccountManager.get(syncManager)
                             .getAccountsByType(Email.EXCHANGE_ACCOUNT_MANAGER_TYPE);
+                        // Make sure we have an up-to-date sAccountList
                         synchronized (sAccountList) {
+                            mAccountObserver.onAccountChanged();
                             reconcileAccountsWithAccountManager(syncManager, sAccountList,
                                     accountMgrList, false, mResolver);
                         }