Bumping gaia.json for 2 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/d6b9476c69b5
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #13333 from bobsilverberg/v1.2ftu

Bug 933980 - [v1.2] Fix test_ftu_with_tour.py and reenable on v1.2

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https://hg.mozilla.org/integration/gaia-1_2/rev/917b8f520e07
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Bug 933980 - [v1.2] Fix test_ftu_with_tour.py and reenable on v1.2