In addition to moving this functionality to oe.license, makes the string
preparation more picky before passing it off to the ast compilation. This
ensures that LICENSE entries like 'GPL/BSD' are seen as invalid (due to the
presence of the unsupported '/').
(From OE-Core rev: 20d4068045c76e9dc2aff0c152dd02d6a109c9dd)
Signed-off-by: Christopher Larson <kergoth@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
