smbreadline: switch to new-style readline typedef

smbreadline: switch to new-style readline typedef

Function, CPFunction, CPPFunction and VFunction typedefs are considered
old-style (deprecated) starting from readline 4.2 (circa 2001).
Compatibility typedefs have been in place up to readline 6.2 but were
removed with the 6.3 release thus causing builds to break.
Switch to the new-style specific prototyped typedef.

Return value is unused so the callback should still be void (see
readline/input.c around line 456 in version 6.3).

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Reviewed-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Thu Mar 13 00:21:47 CET 2014 on sn-devel-104

(cherry picked from commit 29d779c7029f89e530994c45ae065707ffd62c43)

Fix bug #10506 - smbreadline doesn't build with readline 6.3.