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/271c8a313ca9
Author: Bob Silverberg <bob.silverberg@gmail.com>
Desc: Merge pull request #13909 from AndreiH/bug941427_v1.2

Bug 941427 - Strenthen is_displayed() and wait for it before dismissing ...

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https://hg.mozilla.org/integration/gaia-1_2/rev/f3cf9478ba74
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 941427 - Strenthen is_displayed() and wait for it before dismissing keyboard