Bluetooth: OPP: Display proper name while cancelling transfer

Saves names of all the selected files to be transferred even
before starting of client thread so that names remain intact
in the outbound information even when the batch is cancelled
from initiator.

Change-Id: I1763e6fee04dc8bbac943ec1db4d739d46f40939
(cherry picked from commit 6bb19d0c0829fc58a369fa7c509e46492ea497c9)
(cherry picked from commit 4ff3f8e74af2570ad560ca8e311e704bb2580a28)
(cherry picked from commit f11f07a1f02f8a9ce726721951a64133e3ec68a7)