If x11 isn't in DISTRO_FEATURES, then an error information "no providers ..." will \
arise. I modified this bb file to disable "dbus-x11" when no x11 in DISTRO_FEATURES.
[YOCTO #1674]
(From OE-Core rev: da2f6a60fe6b06ebffe92c3d99564711071981c9)
Signed-off-by: Xiaofeng Yan <xiaofeng.yan@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>