Move git-p4import.py and Documentation/git-p4import.txt into
a contrib/p4import directory. Add a README there directing
people to contrib/fast-import/git-p4 as a better alternative.
Signed-off-by: Sean Estabrooks <seanlkml@sympatico.ca> Signed-off-by: Junio C Hamano <gitster@pobox.com>