Re-enable AppArmor support

Now that libapparmor1 moved to /lib it is safe to do so. Add versioned
dependency as long as this is still only in experimental.

Closes: #775331

debian/changelog

@@ -24,6 +24,9 @@ systemd (218-4) UNRELEASED; urgency=medium
     scripts. (Closes: #775404)
   * Fix journal forwarding to syslog in containers without CAP_SYS_ADMIN.
     (Closes: #775067)
+  * Re-enable AppArmor support, now that libapparmor1 moved to /lib. Add
+    versioned dependency as long as this is still only in experimental.
+    (Closes: #775331)
 
   [ Christian Kastner ]
   * Use common-session-noninteractive in systemd-user's PAM config, instead of

debian/control

@@ -23,6 +23,7 @@ Build-Depends: debhelper (>= 9),
                gperf,
                libcap-dev,
                libpam0g-dev,
+               libapparmor-dev,
                libaudit-dev,
                libdbus-1-dev (>= 1.3.2),
                libglib2.0-dev (>= 2.22.0),
@@ -53,6 +54,7 @@ Pre-Depends: ${shlibs:Pre-Depends},
 Depends: ${shlibs:Depends},
          ${misc:Depends},
          libsystemd0 (= ${binary:Version}),
+         libapparmor1 (>= 2.9.0-3+exp1),
          util-linux (>= 2.25),
          mount (>= 2.25),
          initscripts (>= 2.88dsf-53.2),