Don't call xdrrec_skiprecord in the non-blocking case. If
__xdrrec_getrec has returned TRUE, then we have a complete request in
the buffer - calling xdrrec_skiprecord is not necessary. In particular,
if there is another record already buffered on the stream,
xdrrec_skiprecord will discard both this request and the next
one, causing the call to xdr_callmsg to fail and the stream to be
closed.

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