Bumping gaia.json for 4 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/156142bd2f6e
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #13877 from Protonk/936646

Bug 936646 - [Messages][Drafts] Implement local storage for drafts fix jshint errors
r=julien

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https://hg.mozilla.org/integration/gaia-central/rev/a45310af08ca
Author: Adam Hyland <protonk@gmail.com>
Desc: Bug 936646 - [Messages][Drafts] Implement local storage for drafts fix jshint errors

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https://hg.mozilla.org/integration/gaia-central/rev/b92f697fa875
Author: Fabrice Desré <fabrice@desre.org>
Desc: Merge pull request #13879 from fabricedesre/fix-ftu

Bug 941071 - b2g desktop doesn't start anymore r=francisco

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https://hg.mozilla.org/integration/gaia-central/rev/f1f6378227ce
Author: Fabrice Desré <fabrice@desre.org>
Desc: Bug 941071 - b2g desktop doesn't start anymore r=francisco