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

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https://hg.mozilla.org/integration/gaia-central/rev/c9da1e12a2e8
Author: RickyChien <ricky060709@gmail.com>
Desc: Merge pull request #18473 from RickyChien/bug-998759

Bug 998759 - Remove chai.js copying when running make update-common r=@yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/b0f18968887f
Author: Ricky Chien <ricky060709@gmail.com>
Desc: Bug 998759 - Remove chai.js copying when running make update-common
Bumping manifests a=b2g-bump