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

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https://hg.mozilla.org/integration/gaia-central/rev/ba01a8c7d836
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #15633 from MBRSL/bug-962487-UI

Bug 962487 - [UITest][UI] refactor tests using Building Blocks, r=gasolin

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https://hg.mozilla.org/integration/gaia-central/rev/8753ca5fe32f
Author: Tom Jao <tjao@mozilla.com>
Desc: Bug 962487 - [UITest][UI] refactor tests using Building Blocks
Bumping manifests a=b2g-bump