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

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https://hg.mozilla.org/integration/gaia-central/rev/3a49ba9087aa
Author: Hubert Figuière <hub@figuiere.net>
Desc: Merge pull request #21701 from hfiguiere/bug981009

Bug 981009 - Check that we have as many timings as we have runs for startup_test. r=eli

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https://hg.mozilla.org/integration/gaia-central/rev/4dde6f7f27e3
Author: Hubert Figuière <hub@figuiere.net>
Desc: Bug 981009 - Check that we have as many timings as we have runs for startup_test.
Bumping manifests a=b2g-bump