Clarify that a new goroutine is not started for each finalizer.
Clarify that a new goroutine is not started for each finalizer.

R=rsc
CC=golang-dev
http://codereview.appspot.com/1698051

apparentlymart/golang,pombredanne/go-deleteme,gnanderson/go,h8liu/golang,gnanderson/go,gnanderson/go,dsriram/golang,pombredanne/go-deleteme,gnanderson/go,pombredanne/go-deleteme,dsriram/golang,ssrl/go,apparentlymart/golang,tv42/old-go,gnanderson/go,pombredanne/go-deleteme,dsriram/golang,apparentlymart/golang,h8liu/golang,dsriram/golang,apparentlymart/golang,h8liu/golang,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,tv42/old-go,h8liu/golang,h8liu/golang,gnanderson/go,h8liu/golang,ssrl/go,tv42/old-go,dsriram/golang,pombredanne/go-deleteme,apparentlymart/golang,tv42/old-go,tv42/old-go,ssrl/go,tv42/old-go,dsriram/golang,ssrl/go,tv42/old-go,dsriram/golang,ssrl/go,pombredanne/go-deleteme,h8liu/golang,gnanderson/go,ssrl/go,ssrl/go