Log Message:
Update to 1.8.1

Upstream changes:
go1.8.1 (released 2017/04/07) includes fixes to the compiler, linker, runtime, \ 
documentation, go command and the crypto/tls, encoding/xml, image/png, net, \ 
net/http, reflect, text/template, and time packages. See the Go 1.8.1 milestone \ 
on our issue tracker for details.