HAL sndmonitor: Improve cleanup on error and deinit

Some resources were still leaked during sndmonitor deinit. That made
tests failed when the hal process had reach its 256 max fd open during
tests.
All file descriptor open during init should now be close during deinit.

Some memory is still leaked but as deinit of the hal is only used for
testing, it is not very important.

Test: vts-tradefed run vts --module VtsHalAudioV2_0Target
Test: call/play music/record/video...
Bug: 36311550
Change-Id: Id681a3d2dfac1692db168691ea33ef2b7d14ab2c
Signed-off-by: Kevin Rocard <krocard@google.com>