Fix double free in WASAPI no positional audio fallback code-path
Fix double free in WASAPI no positional audio fallback code-path

Also explicitly NULL pointers handed to getAndCheckMixFormat for clarity.

SuperNascher/mumble,richard227/mumble,LuAPi/mumble,SuperNascher/mumble,ccpgames/mumble,feld/mumble,ccpgames/mumble,bheart/mumble,Githlar/mumble,Keridos/mumble,Natenom/mumble,Keridos/mumble,austinliou/mumble,feld/mumble,LuAPi/mumble,Githlar/mumble,SuperNascher/mumble,feld/mumble,mbax/mumble,Keridos/mumble,Zopieux/mumble,bheart/mumble,unascribed/mumble,austinliou/mumble,Lartza/mumble,Natenom/mumble,unascribed/mumble,Keridos/mumble,unascribed/mumble,Zopieux/mumble,SuperNascher/mumble,bheart/mumble,Zopieux/mumble,Zopieux/mumble,Lartza/mumble,ccpgames/mumble,mbax/mumble,Githlar/mumble,Githlar/mumble,Lartza/mumble,richard227/mumble,niko20010/mumble,bheart/mumble,unascribed/mumble,SuperNascher/mumble,ccpgames/mumble,austinliou/mumble,unascribed/mumble,niko20010/mumble,richard227/mumble,Natenom/mumble,Zopieux/mumble,niko20010/mumble,richard227/mumble,mbax/mumble,Githlar/mumble,Natenom/mumble,bheart/mumble,mbax/mumble,niko20010/mumble,Keridos/mumble,bheart/mumble,SuperNascher/mumble,mbax/mumble,richard227/mumble,Lartza/mumble,SuperNascher/mumble,Githlar/mumble,feld/mumble,LuAPi/mumble,Zopieux/mumble,mbax/mumble,Natenom/mumble,LuAPi/mumble,Githlar/mumble,richard227/mumble,richard227/mumble,niko20010/mumble,ccpgames/mumble,ccpgames/mumble,LuAPi/mumble,LuAPi/mumble,unascribed/mumble,bheart/mumble,ccpgames/mumble,unascribed/mumble,Lartza/mumble,Natenom/mumble,bheart/mumble,mbax/mumble,austinliou/mumble,austinliou/mumble,ccpgames/mumble,SuperNascher/mumble,austinliou/mumble,feld/mumble,Githlar/mumble,Lartza/mumble,Zopieux/mumble,Natenom/mumble,niko20010/mumble,LuAPi/mumble,Lartza/mumble,niko20010/mumble,Natenom/mumble,richard227/mumble,Lartza/mumble,mbax/mumble,Keridos/mumble,feld/mumble,niko20010/mumble,SuperNascher/mumble,feld/mumble,Keridos/mumble,Keridos/mumble,unascribed/mumble,austinliou/mumble,feld/mumble,LuAPi/mumble,Zopieux/mumble,LuAPi/mumble,austinliou/mumble