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

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https://hg.mozilla.org/integration/gaia-central/rev/512a45823730
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #10868 from jrburke/app-zip

Bug 890182 Allow apps to specify a directory to use for builds, r=ochameau and asuth

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https://hg.mozilla.org/integration/gaia-central/rev/ee0632d5e21d
Author: jrburke <jrburke@gmail.com>
Desc: Bug 890182 Allow apps to specify a directory to use for builds