Bluetooth-OPP: Read share count from OPP manager before transfer starts

This change will ensure that all the selected files in the batch will
be transfered properly. Otherwise, if actual file count is not used
before transfer start then client session will be disconnected after
reaching the count value that is send during session start and remaining
files will be ignored.

Also added pending update flags for any contentresolver changes so that
transfer status can be properly updated.

CRs-Fixed: 785276
Change-Id: Ia9f9d8a953614b2e0945ca9cfbd2ce026dd40e26