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

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https://hg.mozilla.org/integration/gaia-central/rev/70eb86a06bad
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #21750 from davehunt/bug1032745

Bug 1032745 - Use local resources where possible when installing web apps

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https://hg.mozilla.org/integration/gaia-central/rev/6aad99310e84
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 1032745 - Use local resources where possible when installing web apps. r=zcampbell
Bumping manifests a=b2g-bump