Bumping gaia.json for 3 gaia-central revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/87c41a9538b0
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #13536 from KevinGrandon/bug_919927_backout

Revert "Revert "Revert "Merge pull request #13276 from gasolin/issue-919927"""

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https://hg.mozilla.org/integration/gaia-central/rev/bfef14e8afe6
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 919927 - Re-enable geolocation test

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https://hg.mozilla.org/integration/gaia-central/rev/2a94c53792ff
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Revert "Revert "Merge pull request #13276 from gasolin/issue-919927"""

This reverts commit 231840cb0ba4520e003b3f28d47476d9ebfe544b.