Throttle the refresh of the message list as it changes (fixes #2126515)

* Catch onContentChanged and throttle calls to cursor.requery()
* Use 2.5s for now.  This seems to provide excellent responsiveness
  with little apparent latency.
* Also fixes #2135882

Change-Id: I9cab6558c9cfeb1dbdb5fb250f4f04059db324f7
diff --git a/src/com/android/exchange/SyncManager.java b/src/com/android/exchange/SyncManager.java
index 6aae771..aae36f4 100644
--- a/src/com/android/exchange/SyncManager.java
+++ b/src/com/android/exchange/SyncManager.java
@@ -1791,7 +1791,7 @@
                     Mailbox m = Mailbox.restoreMailboxWithId(INSTANCE, mailboxId);
                     if (syncError != null) {
                         syncError.escalate();
-                        INSTANCE.log(m.mDisplayName + " now held for " + syncError.holdDelay + "s");
+                        INSTANCE.log(m.mDisplayName + " held for " + syncError.holdDelay + "ms");
                     } else {
                         errorMap.put(mailboxId, INSTANCE.new SyncError(exitStatus, false));
                         INSTANCE.log(m.mDisplayName + " added to syncErrorMap, hold for 15s");