Bumping gaia.json for 3 gaia-1_3 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_3/rev/07ba5acf90bd
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Merge pull request #15811 from gabrielesvelto/bug-947234-v1.3

Bug 947234 - Improve SMS app launch latency

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https://hg.mozilla.org/integration/gaia-1_3/rev/4bb240dc2c92
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 947234 - Quiet facebook-related errors that aren't really errors

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https://hg.mozilla.org/integration/gaia-1_3/rev/5974c149c2f2
Author: Gabriele Svelto <gsvelto@mozilla.com>
Desc: Bug 947234 - Render the threads incrementally