default-distrovars.inc: remove libidn from LGPLv2_WHITELIST_GPL-3.0

The libidn recipe is now buildable in distros which blacklist
GPL-3.0 without needing to be explicitly whitelisted (since it
provides at least one non GPLv3 package).

(From OE-Core rev: 63d6d014a0a3da8bf5689b27d1155492e2fdb0f2)

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

meta/conf/distro/include/default-distrovars.inc

@@ -23,7 +23,7 @@ DISTRO_FEATURES ?= "${DISTRO_FEATURES_DEFAULT} ${DISTRO_FEATURES_LIBC}"
 IMAGE_FEATURES ?= ""
 
 WHITELIST_GPL-3.0 ?= ""
-LGPLv2_WHITELIST_GPL-3.0 ?= "libidn"
+LGPLv2_WHITELIST_GPL-3.0 ?= ""
 
 COMMERCIAL_AUDIO_PLUGINS ?= ""
 # COMMERCIAL_AUDIO_PLUGINS ?= "gst-plugins-ugly-mad gst-plugins-ugly-mpegaudioparse"