Merge changes I1c396ab2,Ibf0223cc,Ibe49c873,I6aa1bb98,Ib091831c

* changes:
  Make RTA_METRICS parsing work properly.
  Slightly simplify dumping sockets.
  Support specifying attributes in dump requests.
  Don't run the sock_diag tests twice.
  Test for a SOCK_DIAG oops on IPv4-mapped SYN_RECV connections.