Fix a several problems in conversation list

1) When viewing a non-inbox label, the fragment wasn't being
   tagged correctly, so it couldn't be found later
2) Make sure to set sRefreshRequired before calling
   notifyRefreshRequired().  Otherwise isRefreshRequired() would return
   false.
3) Disable the conversation list throttle.  This was causing a delay
   of up to 4 seconds when switching labels (especially noticible when
   switching to a live label).  This is also noticicible when attempting
   to load more conversations in a Gmail label
4) Make sure to notify the data set changed listener in sync() so the UI
   will know that there is new data.

Bug: 6353342
Bug: 6353444

Change-Id: I54b43a2bf9af3fde308a1f703fb2fc61babc9b6b
3 files changed