pl license change

[Petr Pisar]

To whom it may interest, SWI Prologue, known as `pl' package in Fedora,
has changed license from

(GPLv2+ with exceptions or Artistic 2.0) and (GPLv2+ with exceptions)
and LGPLv2+ and LGPLv2 and UCD and Public Domain and GPLv3+

to

(GPLv2+ with exceptions or Artistic 2.0) and (GPLv2+ with exceptions)
and LGPLv2+ and LGPLv2 and UCD and BSD and Public Domain and GPLv2 and
GPLv3+.

This change is in effect since 6.6.0 version which can be found in
Fedora 21.

-- Petr