[transitions] Fix an unknown property warning

[oliviertassinari]

• PR has tests / docs demo, and is linted.
• Commit and PR titles begin with [ComponentName], and are in imperative form: "[Component] Fix leaky abstraction".
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Fix the following warning. We have added the enterTransitionDuration and leaveTransitionDuration on the Slider component but forgotten the Fade one. I think that exposing the two customization by default is the right option as the spec require different values for them.

Warning: Unknown prop transitionDuration on

tag. Remove this prop from the element. For details, see https://fb.me/react-unknown-prop
in div (created by Paper)
in Paper (created by Dialog)
in Transition (created by Slide)
in Slide (created by Dialog)
in div (created by Modal)