Binder: Resolve race condition

The transaction buffer does not be freed before sendReply,
which may result in the next command fails. e.g. If one
application immediately creates another player to play next
video clip after releases the previous one, the setup may
fail for the native player does not be freed and the surface
is still connected to the previous one.

Change-Id: Id4ce215e5558edeb7468c8b08ec939f578beb184
Signed-off-by: Yiming Cao <ym.caoyiming@gmail.com>