Lazy setup go lang for build swarmkit

setup-go-swarmkit.sh

# Install homebrew.
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
# Install go.
brew install go
# Export path as homebrew suggest.
echo export PATH=$PATH:/usr/local/opt/go/libexec/bin >> ~/.bashrc
# Export gopath to $HOME/go
echo 'export GOPATH=$HOME/go' >> ~/.bash_profile
# Excute bash_profile.
. ~/.bash_profile
# Make physical path
mkdir go && cd go
# Get the swarmkit sourcecode.
go get -d github.com/docker/swarmkit
# Get in.
cd src/github.com/docker/swarmkit
# Make binaries from that source.
make binaries
# Export swarmkit path.
echo 'export PATH=$PATH:$HOME/go/src/github.com/docker/swarmkit/bin' >> ~/.bash_profile
# Excute bash_profile.
. ~/.bash_profile