Bumping gaia.json for 2 gaia-1_3 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_3/rev/8721a1230d77
Author: GaryChen(pychen) <mmm198219@gmail.com>
Desc: Merge pull request #15467 from mpizza/Bug_937487_v1.3_KMEventHandler

Bug 937487 - Keyboard won't disappear after focusing an input and then launch an activity. r=alive.

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https://hg.mozilla.org/integration/gaia-1_3/rev/bb6b9d7d56da
Author: mpizza <mmm198219@gmail.com>
Desc: Bug 937487 - Keyboard won't disappear after focusing an input and then launch an activity