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

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https://hg.mozilla.org/integration/gaia-central/rev/d251338e0961
Author: Julien Wajsberg <felash@gmail.com>
Desc: Revert "Bug 1043293 - [Verticalhome] use "touchend" instead of "click" to launch applications r=kgrandon"

This reverts commit 87ffc8423953bf052ed2b953c7f5e0133cbf1384.
Bumping manifests a=b2g-bump