tizenaudio-sink2/source2: Return 0 when closing devices fails

tizenaudio-sink2/source2: Return 0 when closing devices fails

In case of USB devices, closing PCM function could be failed because the
snd node already disappear.

AUDIO_HAL(P 1276, T 3928): tizen-audio-impl-pcm.c: _pcm_close(156) > Error closing PCM handle : No such device
AUDIO_HAL(P 1276, T 3928): tizen-audio-glue.c: audio_close(131) > Failed to close device
PULSEAUDIO(P 1276, T 3928): hal-interface.c: pa_hal_interface_pcm_close(349) > hal_audio_pcm_close error:0x80001005
PULSEAUDIO(P 1276, T 3928): tizenaudio-source2.c: suspend(147) > Error closing PCM device. rtpoll will be stopped anyway
PULSEAUDIO(P 1276, T 3928): tizenaudio-source2.c: suspend(156) > Device suspended...
PULSEAUDIO(P 1276, T 3928): hal-interface.c: pa_hal_interface_pcm_available(360) > Assertion 'pcm_h' failed at src/hal-interface.c:360, function pa_hal_interface_pcm_av
PULSEAUDIO(P 1276, T 1276): source.c: source_set_state(491) > Assertion 'resuming' failed at ../src/pulsecore/source.c:491, function source_set_state(). Aborting.

[Version] 15.0.59
[Issue Type] Bug Fix

Change-Id: I2be4ae86c090a994e6e9227720ea020b6fea25d9
Signed-off-by: Jaechul Lee <jcsing.lee@samsung.com>