bug285: delete invalid map assignment
bug285: delete invalid map assignment

*T2 implements I2, but T2 does not.

R=gri
CC=golang-dev
http://codereview.appspot.com/1613041
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go