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

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https://hg.mozilla.org/integration/gaia-central/rev/58c77ee58a55
Author: Jared Hirsch <ohai@6a68.net>
Desc: Merge pull request #20391 from 6a68/bug-1021428-fmd-offline-error

Bug 1021428 - Show error when FMD button is clicked without network connection

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https://hg.mozilla.org/integration/gaia-central/rev/070de403fd7d
Author: Jared Hirsch <ohai@6a68.net>
Desc: Bug 1021428 - Show error when FMD button is clicked without network connection r=arthurcc
Bumping manifests a=b2g-bump