Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/ceaba9d0c03c
Author: Jim Porter <jporter@mozilla.com>
Desc: Merge pull request #20170 from jimporter/ringtones-fix-tests

Bug 1021994 - Fix ringtones tests

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https://hg.mozilla.org/integration/gaia-central/rev/dc4446054c3b
Author: Jim Porter <jporter@mozilla.com>
Desc: Bug 1021994 - Fix ringtones tests; r=lightsofapollo
Bumping manifests a=b2g-bump