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

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https://hg.mozilla.org/integration/gaia-central/rev/579a49b97b71
Author: Sam Foster <sam@sam-i-am.com>
Desc: Merge pull request #24114 from sfoster/taskmanager-show-while-showing-bug-1068200

Bug 1068200 - Dont show task manager while already showing. r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/5287ca28b4b4
Author: Sam Foster <sfoster@mozilla.com>
Desc: Bug 1068200 - Dont show task manager while already showing. r=alive
Bumping manifests a=b2g-bump