conf/distro/poky-tiny: correctly disable python in opkg-utils

opkg-utils has more than one PACKAGECONFIG option enabled by default so wiping
out PACKAGECONFIG entirely breaks poky-tiny as then opkg-utils doesn't build an
update-alternatives binary.

Instead, use the _remove override to selectively disable Python in opkg-utils,
leaving update-alternatives present.

(From meta-yocto rev: 17d0862ebc3777d148e62fe9b69225eb4de2dfe0)

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-yocto/conf/distro/poky-tiny.conf

@@ -140,4 +140,4 @@ PNBLACKLIST[core-image-x11] = "not buildable with poky-tiny"
 PNBLACKLIST[core-image-weston] = "not buildable with poky-tiny"
 
 # Disable python usage in opkg-utils since it won't build with tiny config
-PACKAGECONFIG_pn-opkg-utils = ""
+PACKAGECONFIG_remove_pn-opkg-utils = "python"