Bumping gaia.json for 2 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/78f20139e426
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Merge pull request #10588 from jonallengriffin/disabledragdrop

Bug 886602 - Disable homescreen dragdrop test in TBPL for orange, r=mdas...

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https://hg.mozilla.org/integration/gaia-central/rev/96fe54549571
Author: Jonathan Griffin <jgriffin@mozilla.com>
Desc: Bug 886602 - Disable homescreen dragdrop test in TBPL for orange, r=mdas, a=test-only