Bug 8997: change libreplace GPL source to LGPL

Bug 8997: change libreplace GPL source to LGPL

libreplace currently includes socket.c and getifaddrs.c both of which
are GPL licensed.
Although not required, talloc and tdb build alongside this source,
leading to some ambiguity regarding their LGPL licences.

The following copyright holders have agreed to the GPL->LGPL change:
lib/replace/getifaddrs.c
   Copyright (C) Andrew Tridgell 1998
   Copyright (C) Jeremy Allison 2007
   Copyright (C) Jelmer Vernooij <jelmer@samba.org> 2007

lib/replace/test/getifaddrs.c
lib/replace/socket.c
 * Copyright (C) Michael Adam <obnox@samba.org> 2008

Signed-off-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit 8a6743e4edcdff1c7860d150720483f19f3b33bb)