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

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https://hg.mozilla.org/integration/gaia-central/rev/4b2aa13b369b
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #19217 from jrburke/bug1009900-email-compose-blue-line

Bug 1009900 - [email] blue focus line in compose r=mcav

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https://hg.mozilla.org/integration/gaia-central/rev/2431c17b887d
Author: jrburke <jrburke@gmail.com>
Desc: Bug 1009900 - [email] blue focus line in compose
Bumping manifests a=b2g-bump