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

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https://hg.mozilla.org/integration/gaia-central/rev/54706e2b9f1a
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Merge pull request #17717 from dmarcos/bug985578

Bug 985578 - [Camera] [Madai] [Mozilla][UX] Self-Timer not to spec

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https://hg.mozilla.org/integration/gaia-central/rev/1d510b689e9f
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 985578 - [Camera] [Madai] [Mozilla][UX] Self-Timer not to spec
Bumping manifests a=b2g-bump