[MacPorts] #50996: vips: fix python variants

[MacPorts]

#50996: vips: fix python variants
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 Reporter:  ryandesign@…  |      Owner:  jcupitt@…
     Type:  defect        |     Status:  new
 Priority:  Normal        |  Milestone:
Component:  ports         |    Version:  2.3.4
 Keywords:                |       Port:  vips
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 In the vips port, the python variants should be declared as conflicting
 with one another.

 And the python27 variant should only be made the default if the user has
 not already selected one of the other python variants.

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Ticket URL: <https://trac.macports.org/ticket/50996>
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