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

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https://hg.mozilla.org/integration/gaia-1_2/rev/2265a61e1543
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #12635 from gasolin/issue-921327

Bug 921327 - [Flatfish][homescreen] show 6 icons in a row on tablet, r=crdlc
(cherry picked from commit 128c8a9a8a3499ddbc9ef3cd94e4687a076f06ba)