libsemanage: cleanup python use and license definition

The original package supported python on target, now we just use
it as part of the host tools.  The license was also mis-assigned.

[Thomas: add removed option to Config.in.legacy.]

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>