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/a7691fba10b5
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #13445 from davidflanagan/bug935629

Bug 935629: verify picked ringtones before saving them r=dkuo

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https://hg.mozilla.org/integration/gaia-1_2/rev/c11c8ca8a18d
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Bug 935629: verify picked ringtones before saving them