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

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https://hg.mozilla.org/integration/gaia-central/rev/1e92e8607b4c
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #15101 from MBRSL/bug-931655-fm

Bug 931655 - [HW test] Simple FM app implementation, r=pzhang

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https://hg.mozilla.org/integration/gaia-central/rev/4cabbbaf5665
Author: Tom Jao <tjao@mozilla.com>
Desc: Bug 931655 - [HW test] Simple FM app implementation, r=pzhang