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

========

https://hg.mozilla.org/integration/gaia-central/rev/bb58a26fcdd0
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #18553 from gasolin/issue-973445

Bug 973445 - [settings] refactor Sound panel with AMD pattern, r=arthur

========

https://hg.mozilla.org/integration/gaia-central/rev/e98d8f7c9fc2
Author: gasolin <gasolin@gmail.com>
Desc: Bug 973445 - [settings] refactor Sound panel with AMD pattern

- add tone tests
Bumping manifests a=b2g-bump