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

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https://hg.mozilla.org/integration/gaia-central/rev/158fb07e2e49
Author: Hubert Figuière <hub@figuiere.net>
Desc: Merge pull request #21543 from eliperelman/bug-1036436-add-video-to-perf-startup-whitelist

Bug 1036436 - Add video app to performance startup whitelist r=hub

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https://hg.mozilla.org/integration/gaia-central/rev/2d977e34d23e
Author: Eli Perelman <eli@eliperelman.com>
Desc: Bug 1036436 - Add video app to performance startup whitelist
Bumping manifests a=b2g-bump