Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/9c527bfaea4e
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #15675 from crh0716/959962

Bug 959962 - Set correct width based on the padding r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/29cf6eacff16
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 959962 - Set correct width based on the padding

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https://hg.mozilla.org/integration/gaia-central/rev/e2d4ddf0d63c
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Merge pull request #15788 from gregorwagner/disable

Bug 965083 - Disable failing unit tests for a green tbpl. r=jgriffin

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https://hg.mozilla.org/integration/gaia-central/rev/76d2300b80b5
Author: Gregor Wagner <anygregor@gmail.com>
Desc: Disable failing unit tests
Bumping manifests a=b2g-bump