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

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https://hg.mozilla.org/integration/gaia-central/rev/62c4dbd08a61
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #21631 from etiennesegonzac/bug-1030433

Bug 1030433 - Always open target=_blank links/window.open outside of the app r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/87994d876ecd
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1030433 - Always open target=_blank links/window.open outside of the app
Bumping manifests a=b2g-bump