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

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https://hg.mozilla.org/integration/gaia-central/rev/315b9974356f
Author: Arthur Chen <crh0716@gmail.com>
Desc: Revert "Bug 964180 - Introduce AMD to settings app"

This reverts commit d9fb81e2d83dae21e53496b697cdd10ad6a2d4fd.

Conflicts:
	apps/communications/dialer/test/unit/multi_sim_action_button_test.js
	apps/settings/index.html

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https://hg.mozilla.org/integration/gaia-central/rev/1bd507e97ee3
Author: Arthur Chen <crh0716@gmail.com>
Desc: Revert "Bug 985409 -  Fix JSHint issues with test/unit/setup.js"

This reverts commit 5d3e2618af85aa245e4bc06692b9d5df32687745.
Bumping manifests a=b2g-bump