Apply blocking policy in case of prepare() functions

Apply blocking policy in case of prepare() functions

If audio io handle uses media session with MIX_WITH_OTHERS option and other process
has already acquired a focus which has more higher priority than media, policy error
will be returned from prepare() functions.
 - audio_out_prepare(), audio_in_prepare()

Unnecessary session backward compatibility codes are also removed in some functions
exported since tizen 3.0.
 - audio_out_pause(), audio_in_pause()
 - audio_out_resume(), audio_in_resume()

Original patch is
 : https://review.tizen.org/gerrit/#/c/125413/

[Version] 0.4.1
[Profile] Common
[Issue Type] Backward compatibility

Change-Id: Id0710c2847903cf96cdce38eab909b5c2e103c5f
Signed-off-by: Sangchul Lee <sc11.lee@samsung.com>
(cherry picked from commit 6035bcf1a578fa1c0533a7d850e0e9f2794a46ab)