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

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https://hg.mozilla.org/integration/gaia-central/rev/a117a4c6ffcb
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #15025 from gasolin/issue-956634

Bug 956634 - [jsdoc] Enable generate all apps/ jsdoc, r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/1cfabfa337da
Author: gasolin <gasolin@gmail.com>
Desc: Bug 956634 - [jsdoc] Enable generate all apps/ jsdoc

- auto load grunt tasks
- use jsdoc.json for each app
Bumping manifests a=b2g-bump