Recognize version string "0.12" in recent OpenOCD master

Recognize version string "0.12" in recent OpenOCD master

Starting from 5e7612eb4, OpenOCD identifies itself as 0.12.
This causes Microwatt's flash-arty script to fail.  Because neither
the cfg nor the proxy bitstream are affected, we can keep treating
everything as indistinguishable from 0.11.  This patch simply tests
for "0.12" as an alias; it would probably be better to replace this
confusing terminology with something like "single-tap/multi-tap".

Signed-off-by: Boris Shingarov <shingarov@labware.com>