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

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https://hg.mozilla.org/integration/gaia-central/rev/231ca8b58142
Author: root <root@vivien-clam>
Desc: Revert "Bug 920561 - Ensure LazyLoader.load does not slow down app rendering. r=mbudzynski,kgrandon"

This reverts commit 8ed692c6c6df1fcabe3c65ca8fee9cd54e625244.