- Handle setting of existing EA by retrying without XATTR_CREATE.

- Handle setting of existing EA by retrying without XATTR_CREATE.
- Check RESEND instead of RECOVERY in ptlrpc_check_reply, because that's
  what ptlrpc_resend_req sets.
- Don't "commit" in-flight requests.
- Update imp_handle when sending delayed requests after recovery.

Recovery now successfully replays enough to resume the request stream
for the client process.  (That stream may, in the close case, refer to
stale data, but that's the next bit.)