Adds support for Setuid/Setgid calls that has been removed from
go HEAD and won't be available in go 1.4.

Docker-DCO-1.1-Signed-off-by: Mrunal Patel <mrunalp@gmail.com> (github: mrunalp)
Merge pull request #228 from mrunalp/support_removed_syscalls

Adds support for Setuid/Setgid calls that has been removed from go 1.4