swagger: Add missing documentation dependency
swagger: Add missing documentation dependency

When running ciao-controller documentation auto-generation, it recently
due a missing dependency ``golang.org/x/sys/unix``

Below is an example of how it was failing:
```
$GOPATH/bin/swagger  -apiPackage=github.com/01org/ciao/ciao-controller -mainApiFile=github.com/01org/ciao/ciao-controller/main.go -format=markdown -contentsTable=false -models=false -vendoringPath $HOME/gopath/src/github.com/01org/ciao/vendor
2016/11/10 20:38:31 Start parsing
2016/11/10 20:38:33 Can not find package golang.org/x/sys/unix
```

Signed-off-by: Munoz, Obed N <6e5b23a9efbce03e6440ea9b699a6874389894d3@intel.com>

01org/ciao,erick0z/ciao,obedmr/ciao,markdryan/ciao,mrkz/ciao,tpepper/ciao,kaccardi/ciao,mcastelino/ciao,ciao-project/ciao,wcwxyz/ciao,tpepper/ciao,matthewrsj/ciao,mcastelino/ciao,tpepper/ciao,wcwxyz/ciao,kaccardi/ciao,obedmr/ciao,mrkz/ciao,obedmr/ciao,rbradford/ciao,rbradford/ciao,mcastelino/ciao,matthewrsj/ciao,markdryan/ciao,mrkz/ciao,erick0z/ciao,matthewrsj/ciao,wcwxyz/ciao,erick0z/ciao,01org/ciao,ciao-project/ciao