travis: fix go1.7 context check
travis: fix go1.7 context check


GoogleCloudPlatform/golang-samples,danicat/golang-samples,adamyanliev/golang-samples,adamyanliev/golang-samples,adamyanliev/golang-samples,danicat/golang-samples,GoogleCloudPlatform/golang-samples,adamyanliev/golang-samples,danicat/golang-samples,GoogleCloudPlatform/golang-samples