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

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https://hg.mozilla.org/integration/gaia-central/rev/0790c974385d
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #14957 from crh0716/909266

Bug 909266 - Add settings helper for roaming perference r=alive, jaoo

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https://hg.mozilla.org/integration/gaia-central/rev/b331fc595656
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 909266 - Add settings helper for roaming perference

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https://hg.mozilla.org/integration/gaia-central/rev/fae8f318c43e
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #15131 from KevinGrandon/bug_957930_clear_results_on_close

Bug 957930 - [Search] Old results should not display when opening the search app r=daleharvey,benfrancis

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https://hg.mozilla.org/integration/gaia-central/rev/fbc6ff5bc164
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 957930 - [Search] Results should clear after closing the search app