Bumping gaia.json for 2 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/2000928c2478
Author: Jan Jongboom <janjongboom@gmail.com>
Desc: Merge pull request #12448 from comoyo/render_speed

Bug 875963 - Switch case without rebuilding keyboard. r=RudyL

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https://hg.mozilla.org/integration/gaia-central/rev/25e64049e7ef
Author: Jan Jongboom <janjongboom@gmail.com>
Desc: Bug 875963 - Switch case without rebuilding keyboard