gnome-common: Fix license
gnome-common 2.28 is GPLv2+. From Christian Persch, upstream:
The licence is presumed GPL2+, although it's not there explicitly. GPL2+
because as far as I could figure out when I tried to, gnome-autogen started in
gnome-core which had a GPL2 COPYING file.
(From OE-Core rev:
1d1532f495041ac58aeafd06781ac87ee3bd3f6a)
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>