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

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https://hg.mozilla.org/integration/gaia-central/rev/415520315b04
Author: Hubert Figuière <hub@figuiere.net>
Desc: Merge pull request #25941 from hfiguiere/bug1093219-m3u

Bug 1093219 - m3u parsing. r=djf

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https://hg.mozilla.org/integration/gaia-central/rev/491d7b51b14c
Author: Hubert Figuière <hub@figuiere.net>
Desc: Bug 1093219 - m3u parsing. r=djf
Bumping manifests a=b2g-bump