Fix rmi -f removing multiple tags

When an image has multiple tags and rmi is called with force on a tag, only the single tag should be removed.
The current behavior is broken and removes all tags and the image.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)

daemon/image_delete.go

@@ -84,6 +84,11 @@ func (daemon *Daemon) ImageDelete(imageRef string, force, prune bool) ([]types.I
 		daemon.EventsService.Log("untag", img.ID, "")
 		records = append(records, untaggedRecord)
 
+		// If has remaining references then untag finishes the remove
+		if daemon.repositories.HasReferences(img) {
+			return records, nil
+		}
+
 		removedRepositoryRef = true
 	} else {
 		// If an ID reference was given AND there is exactly one

integration-cli/docker_cli_rmi_test.go

@@ -193,6 +193,31 @@ func (s *DockerSuite) TestRmiWithMultipleRepositories(c *check.C) {
 	c.Assert(out, checker.Contains, "Untagged: "+newTag)
 }
 
+func (s *DockerSuite) TestRmiForceWithMultipleRepositories(c *check.C) {
+	testRequires(c, DaemonIsLinux)
+	imageName := "rmiimage"
+	tag1 := imageName + ":tag1"
+	tag2 := imageName + ":tag2"
+
+	_, err := buildImage(tag1,
+		`FROM scratch
+		MAINTAINER "docker"`,
+		true)
+	if err != nil {
+		c.Fatal(err)
+	}
+
+	dockerCmd(c, "tag", tag1, tag2)
+
+	out, _ := dockerCmd(c, "rmi", "-f", tag2)
+	c.Assert(out, checker.Contains, "Untagged: "+tag2)
+	c.Assert(out, checker.Not(checker.Contains), "Untagged: "+tag1)
+
+	// Check built image still exists
+	images, _ := dockerCmd(c, "images", "-a")
+	c.Assert(images, checker.Contains, imageName, check.Commentf("Built image missing %q; Images: %q", imageName, images))
+}
+
 func (s *DockerSuite) TestRmiBlank(c *check.C) {
 	testRequires(c, DaemonIsLinux)
 	// try to delete a blank image name