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

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https://hg.mozilla.org/integration/gaia-central/rev/e47584afe90d
Author: Martijn <martijn.martijn@gmail.com>
Desc: Merge pull request #26695 from mwargers/fullscreen4

Bug 982839 - Write a test to protect against the regression seen in bug ...

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https://hg.mozilla.org/integration/gaia-central/rev/3129a484e8e6
Author: Martijn Wargers <mwargers@mozilla.com>
Desc: Test to protect against regression in bug 981804 (navigate out of fullscreen video), r=gmealer, florin.strugariu
Bumping manifests a=b2g-bump