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

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https://hg.mozilla.org/integration/gaia-central/rev/9a81caa1fdec
Author: Jim Porter <jporter@mozilla.com>
Desc: Merge pull request #16869 from jimporter/music2-gitignore

Bug 979647 - Fix .gitignore for music2 [NPOTB]; r=djf

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https://hg.mozilla.org/integration/gaia-central/rev/fc245f00c6a2
Author: Jim Porter <jporter@mozilla.com>
Desc: Fix .gitignore for music2 [NPOTB]
Bumping manifests a=b2g-bump