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

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https://hg.mozilla.org/integration/gaia-central/rev/5d706512ebb7
Author: Trif Andrei-Alin <trifandreialin@gmail.com>
Desc: Merge pull request #13880 from teodosia/power-save-mode

Bug 938208 - Write test to enable Power Save mode

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https://hg.mozilla.org/integration/gaia-central/rev/aadc92c43cd0
Author: Teodosia Pop <teodosia.pop@gmail.com>
Desc: Bug 938208 - Write test to enable Power Save mode