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/12133d882b77
Author: Marcus Cavanaugh <m@mcav.com>
Desc: Merge pull request #13811 from mcav/fix-gmail-email-polling-v1.2

Bug 933079 - [e-mail] gmail connections not noticing new messages properly. r=asuth a=koi+

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https://hg.mozilla.org/integration/gaia-1_2/rev/5e2d8033de49
Author: Marcus Cavanaugh <m@mcav.com>
Desc: Bug 933079 - [e-mail] gmail connections not noticing new messages properly