Do not close dump file descriptor

The dump caller should close the file descriptor(fd), close fd after
bluetooth dump will cause fd be closed twice.

Bug:116831525
Bug:121049917
Test: Run BT off/on with headset connected test 10000 times.
Change-Id: I59b60043a0a346de9ec7ebadb91c55d0dcea6e2a
Merged-In: Id351b5429cb17b48e37313850a363d739d78c4a1