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/c5b3ee066f88
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #12724 from teodosia/xfail-videoplayer-tests

Bug 924367 - Xfailed videoplayer tests with bug 874897 aurora

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https://hg.mozilla.org/integration/gaia-1_2/rev/6f9f7bfeccd4
Author: Teodosia Pop <teodosia.pop@gmail.com>
Desc: Bug 924367 -  Fix videoplayer tests on aurora