core: 'dlnaManaged' must not be set by client
core: 'dlnaManaged' must not be set by client

'dlnaManaged' attribute must not be set by client on newly created item.

This satisfies DLNA CTT testcase 7.3.133.6.

Pelagicore/Media-Manager-Rygel-patched,Tarnyko/rygel,jku/rygel,Pelagicore/Media-Manager-Rygel-patched,GNOME/rygel,Tarnyko/rygel,Pelagicore/Media-Manager-Rygel-patched,jku/rygel,GNOME/rygel,luisbg/rygel,GNOME/rygel