doc: remove a insignificant line from go1.2.txt
doc: remove a insignificant line from go1.2.txt

Not a user-visible API change.  Just a minor garbage
win in contrived cases.

Also, the package is io/ioutil.

R=golang-dev, r
CC=golang-dev
https://codereview.appspot.com/12987044

apparentlymart/golang,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,tv42/old-go,apparentlymart/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,apparentlymart/golang,apparentlymart/golang,pombredanne/go-deleteme,pombredanne/go-deleteme,pombredanne/go-deleteme,apparentlymart/golang,tv42/old-go,tv42/old-go,pombredanne/go-deleteme,tv42/old-go,tv42/old-go,tv42/old-go,tv42/old-go