skip clouddns test when gcloud isn't initialized

If gcloud hasn't been installed, or if it has but the default application credential file
at .config/gcloud/application_default_credentials.json hasn't been configured, this test
would segfault since the assertion at the start fails but doesn't stop the test

Signed-off-by: Ashley Davis <ashley.davis@jetstack.io>

pkg/issuer/acme/dns/clouddns/clouddns_test.go

@@ -109,6 +109,10 @@ func TestLiveGoogleCloudCleanUp(t *testing.T) {
 }
 
 func TestDNSProvider_getHostedZone(t *testing.T) {
+	if !gcloudLiveTest {
+		t.Skip("skipping live test")
+	}
+
 	testProvider, err := NewDNSProviderCredentials("my-project", util.RecursiveNameservers, "test-zone")
 	assert.NoError(t, err)