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

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https://hg.mozilla.org/integration/gaia-central/rev/510a2b53de76
Author: mozshiao9 <mshiao@mozilla.com>
Desc: Merge pull request #10483 from mozshiao9/master_fm_876265

Bug 876265 - One FM test fails on TBPL, r=pinzhang

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https://hg.mozilla.org/integration/gaia-central/rev/7a1adb90e971
Author: Mark Shiao <mshiao@mozilla.com>
Desc: Bug 876265 - One FM test fails on TBPL