Bumping gaia.json for 2 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/1b2749831fc2
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Merge pull request #11169 from jonallengriffin/bug898108

Bug 898108 - Disable frequently failing test in TBPL, a=test-only

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https://hg.mozilla.org/integration/gaia-central/rev/633ef140b5d1
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Bug 898108 - Disable frequently failing test in TBPL, a=test-only