Bumping gaia.json for 3 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/6143360dd85c
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #13307 from bobsilverberg/cp12265

Bug 934137 - [v1.2] Update cards view app and tests to be in line with master

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https://hg.mozilla.org/integration/gaia-1_2/rev/f10cc7650fd7
Author: Bebe <bebe@mozilla.ro>
Desc: Bug 920449 - Refactor test_cards_view_with_one_app.py

Conflicts:
	tests/python/gaia-ui-tests/gaiatest/tests/functional/cards_view/manifest.ini

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https://hg.mozilla.org/integration/gaia-1_2/rev/46e83ab42978
Author: Ana Hristova <ana.nikolaeva@gmail.com>
Desc: Bug 917207 - Create a system region for cards view and migrate tests to use it