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

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https://hg.mozilla.org/integration/gaia-central/rev/ac5067e8cc18
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #15938 from AndreiH/bug964820

Bug 964820 - Re-enable test_cards_view_kill_apps_with_two_apps on device

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https://hg.mozilla.org/integration/gaia-central/rev/775716fc21d9
Author: Andrei Hutusoru <andreihutusoru@P5069.(none)>
Desc: Bug 964820 - Re-enable test_cards_view_kill_apps_with_two_apps on device
Bumping manifests a=b2g-bump