Add FreeBSD & OpenBSD to crossbinary

[geoffgarside]

Closes #923

Binaries are successfully built via the script/crossbinary.

While I've not got an OpenBSD server or VM to hand, I've tested the go + glide method on a FreeBSD server, a go build completes successfully however a go test $(glide novendor) has a build failure in github.com/containous/traefik/integration as follows

# go test github.com/containous/traefik/integration
# github.com/containous/traefik/vendor/github.com/docker/docker/pkg/mount
cc: warning: argument unused during compilation: '-gno-record-gcc-switches'
# github.com/containous/traefik/vendor/github.com/docker/docker/pkg/mount
cc: warning: argument unused during compilation: '-pthread'
cc: warning: argument unused during compilation: '-gno-record-gcc-switches'
# github.com/containous/traefik/vendor/github.com/docker/docker/runconfig/opts
vendor/github.com/docker/docker/runconfig/opts/parse.go:530: flags.Changed undefined (type *pflag.FlagSet has no field or method Changed)
FAIL	github.com/containous/traefik/integration [build failed]

but I'm not really familiar enough with Docker to know whether these would be expected on FreeBSD or if they are a current issue for Linux as well.

The other packages (those with tests) all pass.

[errm]

I think the test fail might just be caused by vendoring issues. The integration tests have there own and separate vendor folder due to some incompatibilities between different versions of pflag.

Could you try

cd integration && glide install
cd ..
script/test-integration
``

[vdemeester]

LGTM 🐡
/me waiting for @emilevauge opinion

[geoffgarside]

Doing glide install in the integration folder gets things to build a bit further, but they seem to assume the presence of a Docker service, the script/test-integration also assumes Docker is present (also that bash is at /bin/bash rather than /usr/local/bin/bash)

I'm currently doing this in a jail, so I'm not sure what hoops I'd need to jump through to get Docker working inside it, I've only had mixed success with Docker on FreeBSD on bare or vm servers.

[emilevauge]

LGTM
Thanks @geoffgarside
Even if travis builds will be slower than today :'(

[geoffgarside]

Ouch that is a long build time :'(