Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/056dbe15b2aa
Author: Julien Wajsberg <felash@gmail.com>
Desc: Bug 1033403 - [Messages] We don't stop rendering if we tap "back" too soon r=azasypkin

* moves the moment "initializeRendering" is called: in beforeEnter instead of
afterEnter.
* calls MessageManager.markThreadRead in afterEnterThread
* removes the 'done' handler in renderMessages because we don't need it now
Bumping manifests a=b2g-bump