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

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https://hg.mozilla.org/integration/gaia-central/rev/a2f40dcb6d96
Author: Yura Zenevich <yura.zenevich@gmail.com>
Desc: Merge pull request #20089 from yzen/bug-1021137

Bug 1021137 - added missing aria attributes the the lockscreen's passcod...

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https://hg.mozilla.org/integration/gaia-central/rev/df230835fcec
Author: Yura Zenevich <yzenevich@mozilla.com>
Desc: Bug 1021137 - added missing aria attributes the the lockscreen's passcode panel and media container. r=alive
Bumping manifests a=b2g-bump