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

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https://hg.mozilla.org/integration/gaia-central/rev/611780029532
Author: Min-Zhong "John" Lu <mnjul@users.noreply.github.com>
Desc: Merge pull request #20648 from mnjul/bug_1024845_lockscreen_asset_swap

Bug 1024845 - Lockscreen Visual Refresh follow-up: Assets Swap. r=gweng

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https://hg.mozilla.org/integration/gaia-central/rev/c82f744b416b
Author: John Lu [:mnjul] <jlu@mozilla.com>
Desc: Bug 1024845 - Lockscreen Visual Refresh follow-up: Assets Swap
Bumping manifests a=b2g-bump