Revert "When calling openocd from a shell like this:"

This reverts commit e8641695

Original premise was wrong. Proper command is "shutdown", not "exit".

Change-Id: I07f5fe0dda9c24abe53628da986bfda0e406bb4a
Signed-off-by: Alex Austin <alex.austin@spectrumdsi.com>
Reviewed-on: http://openocd.zylin.com/757


Tested-by: jenkins
Reviewed-by: Peter Stuge <peter@stuge.se>