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

========

https://hg.mozilla.org/integration/gaia-central/rev/a9e361af7271
Author: Wilson Page <wilsonpage@me.com>
Desc: Merge pull request #22364 from wilsonpage/1046791

Bug 1046791 - Replace shared/elements/gaia_header with external component

========

https://hg.mozilla.org/integration/gaia-central/rev/ac5f6b163371
Author: Wilson Page <wilsonpage@me.com>
Desc: Bug 1046791 - Replace shared/elements/gaia_header with external component
Bumping manifests a=b2g-bump