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

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https://hg.mozilla.org/integration/gaia-central/rev/2e68c5fe7182
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #13266 from qdot/933402-b2g-really-clean

Bug 933402 - Remove b2g in really-clean target

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https://hg.mozilla.org/integration/gaia-central/rev/4d8655659ad0
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Bug 933402 - Remove b2g in really-clean target