Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-2_0/rev/439374bba8d5
Author: DouglasSherk <github@sherk.me>
Desc: Revert "Merge pull request #20674 from nullaus/bug1021857"

This reverts commit 9b324279fb2225154a50748cb83aa925de4fd11e.
Bumping manifests a=b2g-bump