Log Message:
Update net/arping to 2.18.
--------------------------
Explicit ChangeLog not found, but diff between source may say
following changes.
2.17
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  usage: arping [ -0aAbdDeFpPqrRuUv ] [ -w <us> ]

  -w     Time to wait between pings, in microseconds.
  -W     Same as -w, but in floating point seconds.
2.18
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  usage: arping [ -0aAbdDeFpPqrRuUv ] [ -w <sec> ]

  -w sec Specify a timeout before ping exits regardless of how many
     packets have been sent or received.
  -W sec Time to wait between pings.