asn1: marshal true as 255, not 1.
asn1: marshal true as 255, not 1.

OS X, at least, appears to test |byte == 255|, not |byte != 0| to
establish if a bool is true or false.

R=golang-dev, r
CC=golang-dev
http://codereview.appspot.com/4128064
abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go,abustany/go