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

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https://hg.mozilla.org/integration/gaia-central/rev/977f0de293b1
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #19391 from etiennesegonzac/bug-1012544

Bug 1012544 - Always resize the homescreen if loaded when a system-resize occurs r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/612a44476b94
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 1012544 - Always resize the homescreen if loaded when a software-button-change occurs.
Bumping manifests a=b2g-bump