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

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https://hg.mozilla.org/integration/gaia-central/rev/be6f9fcb4dfd
Author: Julien Wajsberg <felash@gmail.com>
Desc: Merge pull request #17903 from julienw/991063-bail-out-early-if-getDataStores-unavailable

Bug 991063 - [Facebook] Don't fail badly when getDataStores is unavailab...

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https://hg.mozilla.org/integration/gaia-central/rev/d17ef370a3d2
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 991063 - [Facebook] Don't fail badly when getDataStores is unavailable r=jmcf
Bumping manifests a=b2g-bump