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

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https://hg.mozilla.org/integration/gaia-central/rev/9781ab7ef448
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #16135 from crdlc/bug-970267

Bug 970267 - [Download Manager] confirmation screen is displayed twice w...

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https://hg.mozilla.org/integration/gaia-central/rev/a0795dc580d5
Author: crdlc <crdlc@tid.es>
Desc: Bug 970267 - [Download Manager] confirmation screen is displayed twice when we try remove a not supported file
Bumping manifests a=b2g-bump