Cleanup Makefile and .travis.yml (#305)

This fix updates .travis.yml and Makefile for several places:
- Remove unneeded `docker pull gcr.io/google_containers/hyperkube-amd64:v1.2.4` (only v1.3.7 was used)
- Use docker to deploy etcd (insteadof downloading etcd binary).
- Merge `make testk8s` and `make testk8s-setup` (no need to have multiple targets for a couple of tests)
- Set version of etcd and kubernetes in .travis.yml (so that it is easy to update new version in the future)

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

test/kubernetes_test.go

@@ -63,7 +63,7 @@ var testdataLookupSRV = []struct {
 	{"*.*.coredns.local.", 1, 1},                             // One SRV record, via namespace and service wildcard
 }
 
-func TestK8sIntegration(t *testing.T) {
+func TestKubernetesIntegration(t *testing.T) {
 
 	// t.Skip("Skip Kubernetes Integration tests")
 	// subtests here (Go 1.7 feature).