core/legal-info: add package version to license directory

core/legal-info: add package version to license directory

Now that we save the source archives in a directory named after the
package and its version, do the same for the license files, for
consistency.

It has a not-so-bad side-effect of also saving the version string in
the all-licenses list.

The only (small) side-effect, is that the warnings about undefined
_LICENSE_FILES now contains the version string, too. That's unavoidable,
since that's what is stored in the legal report.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Luca Ceresoli <luca@lucaceresoli.net>
Acked-by: Luca Ceresoli <luca@lucaceresoli.net>
Tested-by: Luca Ceresoli <luca@lucaceresoli.net>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>