add apparmor build tag and update readme

Signed-off-by: Xianglin Gao <xlgao@zju.edu.cn>

server/apparmor/apparmor_unsupported.go

@@ -0,0 +1,27 @@
+// +build !apparmor
+
+package apparmor
+
+const (
+	// ContainerAnnotationKeyPrefix is the prefix to an annotation key specifying a container profile.
+	ContainerAnnotationKeyPrefix = "container.apparmor.security.beta.kubernetes.io/"
+
+	// ProfileRuntimeDefault is he profile specifying the runtime default.
+	ProfileRuntimeDefault = "runtime/default"
+	// ProfileNamePrefix is the prefix for specifying profiles loaded on the node.
+	ProfileNamePrefix = "localhost/"
+)
+
+// IsEnabled returns false, when build without apparmor build tag.
+func IsEnabled() bool {
+	return false
+}
+
+// InstallDefaultAppArmorProfile dose nothing, when build without apparmor build tag.
+func InstallDefaultAppArmorProfile() {
+}
+
+// GetProfileNameFromPodAnnotations dose nothing, when build without apparmor build tag.
+func GetProfileNameFromPodAnnotations(annotations map[string]string, containerName string) string {
+	return ""
+}