encode: fix warnings if assertions are disabled
encode: fix warnings if assertions are disabled

Fixes "suggest braces around empty body in an 'else' statement [-Wempty-body]"

mbebenita/daala,mbebenita/daala,kodabb/daala,xiph/daala,felipebetancur/daala,xiphmont/daala,felipebetancur/daala,iankronquist/daala,tribouille/daala,KyleSiefring/daala,felipebetancur/daala,ycho/daala,nvoron23/daala,kustom666/daala,mbebenita/daala,kustom666/daala,xiphmont/daala,felipebetancur/daala,kodabb/daala,kustom666/daala,xiphmont/daala,ascent12/daala,ycho/daala,xiph/daala,HeadhunterXamd/daala,kustom666/daala,iankronquist/daala,nvoron23/daala,tribouille/daala,xiphmont/daala,ascent12/daala,jmvalin/daala,KyleSiefring/daala,jmvalin/daala,ascent12/daala,xiph/daala,nvoron23/daala,nvoron23/daala,ycho/daala,iankronquist/daala,tribouille/daala,kodabb/daala,nvoron23/daala,HeadhunterXamd/daala,mbebenita/daala,luctrudeau/daala,iankronquist/daala,HeadhunterXamd/daala,HeadhunterXamd/daala,luctrudeau/daala,tribouille/daala,ascent12/daala,xiph/daala,xiphmont/daala,jmvalin/daala,HeadhunterXamd/daala,ycho/daala,mbebenita/daala,tribouille/daala,KyleSiefring/daala,jmvalin/daala,luctrudeau/daala,felipebetancur/daala,xiph/daala,iankronquist/daala,luctrudeau/daala,kodabb/daala,kustom666/daala,KyleSiefring/daala,ascent12/daala,KyleSiefring/daala,ycho/daala,jmvalin/daala,kodabb/daala,luctrudeau/daala