Remove the old loading system from compose config loading

The original Compose config loading used the `compose` tag, which
was replaced by mapstructure. Some fields were left on the old tag. This
commit removes the old tag and uses types and mapstructure.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

compose/loader/loader_test.go

@@ -394,7 +394,7 @@ services:
 `)
 	assert.NoError(t, err)
 
-	expected := map[string]string{
+	expected := types.MappingWithEquals{
 		"FOO":  "1",
 		"BAR":  "2",
 		"BAZ":  "2.5",
@@ -456,7 +456,7 @@ volumes:
 
 	home := os.Getenv("HOME")
 
-	expectedLabels := map[string]string{
+	expectedLabels := types.MappingWithEquals{
 		"home1":       home,
 		"home2":       home,
 		"nonexistent": "",
@@ -621,6 +621,10 @@ func TestFullExample(t *testing.T) {
 			"BAR":            "2",
 			"BAZ":            "3",
 		},
+		EnvFile: []string{
+			"./example1.env",
+			"./example2.env",
+		},
 		Expose: []string{"3000", "8000"},
 		ExternalLinks: []string{
 			"redis_1",
@@ -632,10 +636,7 @@ func TestFullExample(t *testing.T) {
 			"somehost":  "162.242.195.82",
 		},
 		HealthCheck: &types.HealthCheckConfig{
-			Test: []string{
-				"CMD-SHELL",
-				"echo \"hello world\"",
-			},
+			Test:     types.HealthCheckTest([]string{"CMD-SHELL", "echo \"hello world\""}),
 			Interval: "10s",
 			Timeout:  "1s",
 			Retries:  uint64Ptr(5),