asn1: fix incorrect prints found by govet
asn1: fix incorrect prints found by govet

R=golang-dev
CC=golang-dev
http://codereview.appspot.com/5449063

Committer: Adam Langley <db68fba232b2c49ed3e9d3081df349dde7b61dfd@golang.org>

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