librdmacm: support querying AF_IB addresses

librdmacm: support querying AF_IB addresses

The current query route command returns path record data and address
information.  The latter is restricted to sizeof(sockaddr_in6).  In
order to support AF_IB, modify the library to use the new query addr
command, which supports larger address sizes and avoids querying for
path records data when none are available.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>