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/57526ffddf01
Author: Trif Andrei-Alin <trifandreialin@gmail.com>
Desc: Merge pull request #12793 from teodosia/enable-dialer-tests

Bug 925702 - Reenable tests/functional/dialer tests on aurora

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https://hg.mozilla.org/integration/gaia-1_2/rev/dd7a1470235e
Author: Teodosia Pop <teodosia.pop@gmail.com>
Desc: Bug 925702 - Reenable tests/functional/dialer tests on aurora