rdma_server: handle IBV_SEND_INLINE correctly

rdma_server: handle IBV_SEND_INLINE correctly

Not all RDMA devices support IBV_SEND_INLINE.  At least some of those
that don't will ignore the flag passed to rdma_post_send and attempt to
send the command by using an sge entry instead.  Because we don't
register the send memory, this fails.  The proper way to deal with the
fact that IBV_SEND_INLINE is not guaranteed is to check the returned
value in our cap struct to see if we have support for inline data, and
if not, fall back to non-inline sends and to register the send memory
region.

Signed-off-by: Doug Ledford <dledford@redhat.com>