Accumulate driver opts with the same key in "docker network connect"

Similar to the "--network driver-opt=", accumulate options with the
same label in "docker network connect --driver-opt=".

Signed-off-by: Rob Murray <rob.murray@docker.com>

cli/command/filename

@@ -0,0 +1,10 @@
+{
+	"auths": {
+		"https://index.docker.io/v1/": {
+			"auth": "dTA6cDA="
+		},
+		"server1.io": {
+			"auth": "dTE6cDE="
+		}
+	}
+}

cli/command/network/connect.go

@@ -87,7 +87,11 @@ func convertDriverOpt(options []string) (map[string]string, error) {
 		if !ok || k == "" {
 			return nil, fmt.Errorf("invalid key/value pair format in driver options")
 		}
-		driverOpt[k] = strings.TrimSpace(v)
+		v = strings.TrimSpace(v)
+		if oldval, ok := driverOpt[k]; ok {
+			v = oldval + "," + v
+		}
+		driverOpt[k] = v
 	}
 	return driverOpt, nil
 }

cli/command/network/connect_test.go

@@ -52,7 +52,8 @@ func TestNetworkConnectWithFlags(t *testing.T) {
 		Links:   []string{"otherctr"},
 		Aliases: []string{"poor-yorick"},
 		DriverOpts: map[string]string{
-			"adriveropt": "anoptval",
+			"driveropt1": "optval1,optval2",
+			"driveropt2": "optval3",
 		},
 	}
 	cli := test.NewFakeCli(&fakeClient{
@@ -67,7 +68,9 @@ func TestNetworkConnectWithFlags(t *testing.T) {
 	cmd.SetArgs(args)
 	for _, opt := range []struct{ name, value string }{
 		{"alias", "poor-yorick"},
-		{"driver-opt", "adriveropt=anoptval"},
+		{"driver-opt", "driveropt1=optval1"},
+		{"driver-opt", "driveropt1=optval2"},
+		{"driver-opt", "driveropt2=optval3"},
 		{"ip", "192.168.4.1"},
 		{"ip6", "fdef:f401:8da0:1234::5678"},
 		{"link", "otherctr"},