mediaplayer: qml: add missing dbus permission in config.xml

mediaplayer: qml: add missing dbus permission in config.xml

To avoid cynara access messages like the following request
dbus permissions. This oddly caused the QML thread to lock up
rendering the Image component with the respective album art.

cynara[334]: User::App::mediaplayer;1001;http://tizen.org/privilege/internal/dbus => DENY
cynara[334]: User::App::mediaplayer;1001;http://tizen.org/privilege/internal/dbus => DENY

Bug-AGL: SPEC-2774
Change-Id: If1e9ff139c91ca2912402a6c2a709df9fdf4aeff
Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>