Retrieve SGID after calling rdma_bind_addr

A change was made to rdma_bind_addr when AF_IB is enabled
to only retrieve the resulting bound address.  Previously,
rdma_bind_addr would retrieve the corresponding SGID as
well.  This breaks some apps which were checking the
SGID after binding to an IP address.  Revert to the
previous behavior of also retrieving the SGID after
calling rdma_bind_addr.