logind: allow unprivileged session-device access

The session-device/control API was introduced for unprivileged device
access from within a session. Add the required dbus policy to the default
logind policies.

Note: logind validates that only root and the user of a session can
use the API. Furthermore, only a single API user gets access at a time.

src/login/org.freedesktop.login1.conf

@@ -148,6 +148,26 @@
                        send_interface="org.freedesktop.login1.Session"
                        send_member="SetIdleHint"/>
 
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Session"
+                       send_member="TakeControl"/>
+
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Session"
+                       send_member="ReleaseControl"/>
+
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Session"
+                       send_member="TakeDevice"/>
+
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Session"
+                       send_member="ReleaseDevice"/>
+
+                <allow send_destination="org.freedesktop.login1"
+                       send_interface="org.freedesktop.login1.Session"
+                       send_member="PauseDeviceComplete"/>
+
                 <allow receive_sender="org.freedesktop.login1"/>
         </policy>