[openib-general] userspace verbs UD support

[Roland Dreier]

I've just committed support for UD address handles to libibverbs and
libmthca on the roland-uverbs branch.  This makes it possible to use
UD from userspace.  libibverbs/examples has a new ud-pingpong.c demo
program that shows how this works.

There are no new changes to the kernel uverbs support on the
roland-uverbs branch to handle UD, so any modules built with last
week's code should still work.

 - R.