Change reset configuration.

This patch change the default reset config from SYSRESETREQ to the working
VECTRESET.

Change-Id: I21a9a74b9c0c68cfa3a6e6dac9b123acc98a93cb
Signed-off-by: Mathias K <kesmtp@freenet.de>
Reviewed-on: http://openocd.zylin.com/1186
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>