Initialize return value.

Initialize return value.

Because no future error checking we will initialize the pointer to
a know value.

Change-Id: I2466eeb413245a398927ec9f3742c2a9a3d51baf
Signed-off-by: Mathias K <kesmtp@freenet.de>
Reviewed-on: http://openocd.zylin.com/283
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-by: Øyvind Harboe <oyvindharboe@gmail.com>