Bumping gaia.json for 3 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/9e2baca92a93
Author: Zac <zcampbell@mozilla.com>
Desc: Bug 1027708 - test_homescreen_edit_mode.py intermittent due to unknown MacOS bug a=testonly r=me

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https://hg.mozilla.org/integration/gaia-central/rev/597b30f1e93f
Author: Ben Francis <ben@tola.me.uk>
Desc: Merge pull request #20742 from pivanov/bug-1026856

Bug 1026856 - [Flame][Browser] Icons in Tabs page should not be scaled while tapping it r=benfrancis

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https://hg.mozilla.org/integration/gaia-central/rev/be707c942358
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 1026856 - [Flame][Browser] Icons in Tabs page should not be scaled while tapping it
Bumping manifests a=b2g-bump