Nicolas Pitre <nico@cam.org> fix "halt 0" to only halt and not to poll/wait...

Nicolas Pitre <nico@cam.org> fix "halt 0" to only halt and not to poll/wait afterwards. This follows the intention in the docs.

git-svn-id: svn://svn.berlios.de/openocd/trunk@1398 b42882b7-edfa-0310-969c-e2dbd0fdcd60