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

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https://hg.mozilla.org/integration/gaia-central/rev/9641667526a4
Author: autolander <kgrandon@mozilla.com>
Desc: Bug 1104991 - merge pull request #26458 from KevinGrandon:bug_1104991_update_gaia_readme to mozilla-b2g:master

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https://hg.mozilla.org/integration/gaia-central/rev/8d9ea178842e
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1104991 - Update gaia README to include autolander details
Bumping manifests a=b2g-bump