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

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https://hg.mozilla.org/integration/gaia-2_1/rev/19c6117c6980
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1074703 - [ValueSelector] Ensure window listener is removed on destroy r=alive r=gasolin
Bumping manifests a=b2g-bump