pidl/ws: Fix Dead Store (Dead assignement/Dead increment) warning found by Clang

pidl/ws: Fix Dead Store (Dead assignement/Dead increment) warning found by Clang

Port Wireshark commit f6b9e7a

Author: Alexis La Goutte <alexis.lagoutte@gmail.com>
Date:   Sun Sep 28 20:57:13 2014 +0200

    PIDL: Fix Dead Store (Dead assignement/Dead increment) warning found by Clang

    Change-Id: Ibae478771b30d6e9ae07315985f1e71bc6b65423
    Reviewed-on: https://code.wireshark.org/review/4350
    Reviewed-by: Michael Mann <mmann78@netscape.net>
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Reviewed-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: David Disseldorp <ddiss@samba.org>