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

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https://hg.mozilla.org/integration/gaia-central/rev/4cfdc152685c
Author: ochameau <poirot.alex@gmail.com>
Desc: Merge pull request #22995 from ochameau/mulet-dt

Bug 1016030 - Fix devtools test on mulet. r=jryans

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https://hg.mozilla.org/integration/gaia-central/rev/a2bfc7b56233
Author: Alexandre Poirot <poirot.alex@gmail.com>
Desc: Bug 1016030 - Fix devtools test on mulet. r=jryans
Bumping manifests a=b2g-bump