Fix integration tests with testRequires(c, Network)

It seems http://hub.docker.com is not accessible anymore, so switching
to https://hub.docker.com for testRequires(c, Network).

Adds a Timeout check on the TestRequirement to *panic* if there is a
timeout (fail fast).

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

integration-cli/requirements.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"os/exec"
 	"strings"
+	"time"
 
 	"github.com/go-check/check"
 )
@@ -37,7 +38,18 @@ var (
 	}
 	Network = TestRequirement{
 		func() bool {
-			resp, err := http.Get("http://hub.docker.com")
+			// Set a timeout on the GET at 15s
+			var timeout = time.Duration(15 * time.Second)
+			var url = "https://hub.docker.com"
+
+			client := http.Client{
+				Timeout: timeout,
+			}
+
+			resp, err := client.Get(url)
+			if err != nil && strings.Contains(err.Error(), "use of closed network connection") {
+				panic(fmt.Sprintf("Timeout for GET request on %s", url))
+			}
 			if resp != nil {
 				resp.Body.Close()
 			}