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

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https://hg.mozilla.org/integration/gaia-central/rev/c93d92738a02
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #24782 from KevinGrandon/bug_1077780_update_settings_shims

Bug 1077780 - [Settings] Update marionette shims r=arthurcc

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https://hg.mozilla.org/integration/gaia-central/rev/f8f43f637de0
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1077780 - [Settings] Update marionette shims r=arthurcc
Bumping manifests a=b2g-bump