Sound error when no sound device or disabled

[Vladislav Belov]

If the sound device is disabled then we have next error on start:

ERROR: Sound: AlcInit failed, m_Device=0x0 m_Context=0x0 dev_name=OpenAL Soft err=a004

And in game:

OpenAL error: (null); called from COggData::InitOggFile (line 74)
ERROR: Failed to create initial buffer. OpenAL error: (null)
ERROR: could not initialize ogg data at audio/voice/latin/civ/civ_male_what_is_it_1.ogg
ERROR: OpenAL error: (null); called from COggData::~COggData (line 36)
ERROR: OpenAL error: (null); called from COggData::~COggData (line 40)
ERROR: OpenAL error: (null); called from COggData::~COggData (line 44)
ERROR: OpenAL error: (null); called from CSoundData::~CSoundData (line 37)
ERROR: OpenAL error: (null); called from CSoundData::~CSoundData (line 41)
ERROR: error loading sound: pathname=audio/voice/latin/civ/civ_male_what_is_it_1.ogg, error=Function failed (no details available)

Second problem, that if we will miss the sound device in game (pull out minijack of headphones) then sound dissapear, and doesn't appear after return headphones on the place.

My suggestions:

• check (nullptr and alc* functions) Device & Context every time when something want to play sound
• show to player nice message that the sound device is missing and sounds will not play.