[openib-general] New uverbs ABI version

[Roland Dreier]

I just checked a change into subversion to implement the completion
channel API I described last week.  This also cleans up some of the
problems in the kernel error paths.

These changes break both the kernel ABI and the userspace library
API, so to use the new code, you will have to update your kernel,
libibverbs, libmthca, and whatever application you are running on top
of libibverbs.  The new libibverbs will work with all old kernels, so
it should be fine to update.

I'll post patches to update MVAPICH and Open MPI to work with the new
libibverbs.  I didn't try to fix uDAPL, because some thought probably
needs to go into how to use completion channels most efficiently.

I've done some testing, but I undoubtedly introduced some new bugs, so
please let me know the results of your testing.

Thanks,
  Roland