Bumping gaia.json for 2 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/571bf4395710
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #14524 from alivedise/bugzilla/946482_v1.2/activity-chaining-done

Bug 946482 - activitydone handler fine tune, r=timdream

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https://hg.mozilla.org/integration/gaia-1_2/rev/9adda225ca26
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 946482 - activitydone handler fine tune