fix this warning:

  net/sunrpc/xprtrdma/verbs.c: In function ‘rpcrdma_conn_upcall’:
  net/sunrpc/xprtrdma/verbs.c:279: warning: unused variable ‘addr’
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>