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

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https://hg.mozilla.org/integration/gaia-central/rev/b7dce66e2f50
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #13278 from MBRSL/bug-929315-geolocation

Bug 929315 - [HW test] geolocation needs permission, r=gasolin

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https://hg.mozilla.org/integration/gaia-central/rev/71e9e89e5197
Author: Tom Jao <tjao@mozilla.com>
Desc: Bug 929315 - [HW test] geolocation needs permission