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

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https://hg.mozilla.org/integration/gaia-central/rev/20f241d3b5c4
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #19386 from etiennesegonzac/bug-1012545

Bug 1012545 - Prevent a fluffing/rendering issue on the add-contact-button r=rik

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https://hg.mozilla.org/integration/gaia-central/rev/94e02a6aaad6
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1012545 - Prevent a fluffing/rendering issue on the add-contact-button.
Bumping manifests a=b2g-bump