change channel read to clear data just read from the channel. this will make it easier to recognize when to garbage collect and finalize.
change channel read to clear
data just read from the channel.
this will make it easier to
recognize when to garbage
collect and finalize.

R=rsc
CC=golang-dev
http://codereview.appspot.com/882043

tav/go,tav/go,tav/go,tav/go,tav/go,tav/go,tav/go