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

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https://hg.mozilla.org/integration/gaia-central/rev/a7268d445315
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 976091 - [Messages][DSDS] Show the SIM information in the message bubble r=azasypkin

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https://hg.mozilla.org/integration/gaia-central/rev/c4917258eb51
Author: Wilson Page <wilsonpage@me.com>
Desc: Merge pull request #22989 from wilsonpage/1054963

Bug 1054963 - Camera app's switch is not changing the camera modes

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https://hg.mozilla.org/integration/gaia-central/rev/4ea8391b96d1
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 1054963 - Camera app's switch is not changing the camera modes
Bumping manifests a=b2g-bump