getting-started/bookshelf: change erroneous continue statement to return
getting-started/bookshelf: change erroneous continue statement to return

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