Use go in travis build to install S2I

.travis.yml

@@ -3,4 +3,14 @@ sudo: required
 services:
   - docker
 
+language: go
+
+go: 1.4
+
+install:
+  - go get github.com/openshift/source-to-image
+  - cd ${GOPATH}/src/github.com/openshift/source-to-image
+  - export PATH=$PATH:${GOPATH}/src/github.com/openshift/source-to-image/_output/local/bin/linux/amd64/
+  - hack/build-go.sh
+
 script: make test