Fixed CANVAS.recycle() occurred NullPointerException on Android 3.x.
Fixed CANVAS.recycle() occurred NullPointerException on Android 3.x.

suckgamony/RapidDecoder,indra7/RapidDecoder,indra7/RapidDecoder,indra7/RapidDecoder,suckgamony/RapidDecoder,suckgamony/RapidDecoder