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

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https://hg.mozilla.org/integration/gaia-central/rev/cf15b014bb45
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #20317 from etiennesegonzac/bug-1021512-homescreen-utility-tray

Bug 1021512 - Send a touchcancel to the active app when the system starts r=21,kgrandon

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https://hg.mozilla.org/integration/gaia-central/rev/c204da3404d6
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1021512 - Send a touchcancel to the active app when the system starts swallowing touch events.
Bumping manifests a=b2g-bump