Reduce GC in Bluetooth application

During OPP transfer, the Bluetooth application uses a ContentProvider
to keep track of how many bytes have been transferred. An update()
is called every 64Kb and in turn causes a couple of query(). One of
the listeners updates a notification. All of this causes a lot of
small memory allocations and means that the GC has to clean up a lot
of objects during transfer.
Partly fixed by only calling update() every percent of transfer
instead of every 64Kb block, which means it works best on large
files.

Change-Id: Ia24b5e460fd52ed066867887ff6d22c579ec8e7e