Fix third party app access to provider

K-9 4.3xx have broken third party unread count readers, such as TeslaUnread/Nova Launcher and MailListWidget for K-9 . This fixes the issue and also fixes a leaked semaphore.

Fixes two issues
1) An exception in the query can cause the semaphore to never be released,
this is now handled in the finally block
2) Binder identity was not cleared preventing access to the EmailProvider