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

========

https://hg.mozilla.org/integration/gaia-central/rev/be086ac51f3b
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Merge pull request #13997 from dominickuo/bug-911108

Bug 911108 - [music] change the hash to mix page when the player is reset by the storages, r=jimporter

========

https://hg.mozilla.org/integration/gaia-central/rev/cd99f77a3112
Author: Dominic Kuo <dkuo@mozilla.com>
Desc: Bug 911108 - [music] change the hash to mix page when the player is reset by the storages