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

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https://hg.mozilla.org/integration/gaia-central/rev/5b157e823d42
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #16514 from etiennesegonzac/missing-git-ignore

Bug 975395 - Add missing gitignores for the directories created by running a make test-integration. r=kgrandon

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https://hg.mozilla.org/integration/gaia-central/rev/b0411430cccd
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 975395 - Add missing gitignores for the directories created by running a make test-integration.
Bumping manifests a=b2g-bump