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

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https://hg.mozilla.org/integration/gaia-central/rev/17c0c36b8588
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #15091 from KevinGrandon/bug_957418_rocketbar_develop_in_browser

Bug 957418 - Fix interapp communication API for Rocketbar r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/88a983068d0e
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 957418 - Fix interapp communication API for Rocketbar