Revert "apparmor: Check if apparmor_parser is available"

This reverts commit ab3fa46.

This fix was partial, and is not needed with the proper fix in
containerd.

Signed-off-by: Bjorn Neergaard <bneergaard@mirantis.com>

daemon/apparmor_default.go

@@ -5,12 +5,9 @@ package daemon // import "github.com/docker/docker/daemon"
 
 import (
 	"fmt"
-	"os"
-	"sync"
 
 	"github.com/containerd/containerd/pkg/apparmor"
 	aaprofile "github.com/docker/docker/profiles/apparmor"
-	"github.com/sirupsen/logrus"
 )
 
 // Define constants for native driver
@@ -19,11 +16,6 @@ const (
 	defaultAppArmorProfile    = "docker-default"
 )
 
-var (
-	checkAppArmorOnce   sync.Once
-	isAppArmorAvailable bool
-)
-
 // DefaultApparmorProfile returns the name of the default apparmor profile
 func DefaultApparmorProfile() string {
 	if apparmor.HostSupports() {
@@ -33,20 +25,7 @@ func DefaultApparmorProfile() string {
 }
 
 func ensureDefaultAppArmorProfile() error {
-	checkAppArmorOnce.Do(func() {
-		if apparmor.HostSupports() {
-			// Restore the apparmor_parser check removed in containerd:
-			// https://github.com/containerd/containerd/commit/1acca8bba36e99684ee3489ea4a42609194ca6b9
-			// Fixes: https://github.com/moby/moby/issues/44900
-			if _, err := os.Stat("/sbin/apparmor_parser"); err == nil {
-				isAppArmorAvailable = true
-			} else {
-				logrus.Warn("AppArmor enabled on system but \"apparmor_parser\" binary is missing, so profile can't be loaded")
-			}
-		}
-	})
-
-	if isAppArmorAvailable {
+	if apparmor.HostSupports() {
 		loaded, err := aaprofile.IsLoaded(defaultAppArmorProfile)
 		if err != nil {
 			return fmt.Errorf("Could not check if %s AppArmor profile was loaded: %s", defaultAppArmorProfile, err)