Log Message:
Pull in https://golang.org/cl/17672, "math/big: fix carry propagation in
Int.Exp Montgomery code", to fix CVE-2015-8618.

From the oss-security posting that asked for a CVE:

"The Go open source project has received notification of an error in the
math/big library (https://golang.org/pkg/math/big/). The problem that was
identified is similar to CVE-2015-3193
<https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3193>. The
vulnerability was introduced in the 1.5 release, and remains present in Go
1.5.1 and 1.5.2.

"A fix for the issue has been applied to the master branch of the Go repo
under CL 17672 <https://go-review.googlesource.com/#/c/17672/>. We will
also be releasing Go 1.5.3 to fix this vulnerability."

ok wiz@