[MC-131246] OpenAL start up logs "No Sound" and "Silent Mode" when it isn't silent

When Minecraft starts, OpenAL writes to the log that it's starting in silent mode. When the game is running sounds are working normally.

10:25:34	diy	Starting up SoundSystem...
10:25:35	diy	Initializing No Sound
10:25:35	diy	(Silent Mode)
10:25:36	diy	OpenAL initialized.
10:25:36	diy	Preloading sound minecraft:sounds/ambient/underwater/underwater_ambience.ogg
10:25:36	diy	Sound engine started

[0612/212828:INFO:GameCallbacks.cpp(178)] game/ciq (Client thread) info Setting user: Kumasasa
[0612/212830:INFO:GameCallbacks.cpp(178)] game/ciq (Client thread) info LWJGL Version: 3.1.2 build 29
[0612/212832:INFO:GameCallbacks.cpp(178)] game/uq (Client thread) info Reloading ResourceManager: Default
[0612/212838:INFO:GameCallbacks.cpp(178)] game/diy (Sound Library Loader) info Starting up SoundSystem...
[0612/212838:INFO:GameCallbacks.cpp(178)] game/diy (Thread-2) info Initializing No Sound
[0612/212838:INFO:GameCallbacks.cpp(178)] game/diy (Thread-2) info (Silent Mode)
[0612/212838:INFO:GameCallbacks.cpp(178)] game/game () error AL lib: (EE) SetChannelMap: Failed to match front-center channel (2) in channel map
  <log4j:Event logger="diy" timestamp="1528831718606" level="INFO" thread="Thread-2">
    <log4j:Message><![CDATA[OpenAL initialized.]]></log4j:Message>
  </log4j:Event>
[0612/212838:INFO:GameCallbacks.cpp(178)] launcher/monitor (Process Monitor) error expected <
[0612/212838:INFO:GameCallbacks.cpp(178)] game/diy (Sound Library Loader) info Preloading sound minecraft:sounds/ambient/underwater/underwater_ambience.ogg
[0612/212838:INFO:GameCallbacks.cpp(178)] game/diy (Sound Library Loader) info Sound engine started
[0612/212841:INFO:GameCallbacks.cpp(178)] game/dfu (Client thread) info Created: 1024x512 textures-atlas