Do not fail when a container is being removed and we request its delete again.

Abort the process and return a success response, letting the original
request finish its job.

Signed-off-by: David Calavera <david.calavera@gmail.com>

daemon/delete_test.go

@@ -0,0 +1,39 @@
+package daemon
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/docker/docker/runconfig"
+)
+
+func TestContainerDoubleDelete(t *testing.T) {
+	tmp, err := ioutil.TempDir("", "docker-daemon-unix-test-")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmp)
+	daemon := &Daemon{
+		repository: tmp,
+		root:       tmp,
+	}
+
+	container := &Container{
+		CommonContainer: CommonContainer{
+			State:  NewState(),
+			Config: &runconfig.Config{},
+		},
+	}
+
+	// Mark the container as having a delete in progress
+	if err := container.setRemovalInProgress(); err != nil {
+		t.Fatal(err)
+	}
+
+	// Try to remove the container when it's start is removalInProgress.
+	// It should ignore the container and not return an error.
+	if err := daemon.rm(container, true); err != nil {
+		t.Fatal(err)
+	}
+}