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

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https://hg.mozilla.org/integration/gaia-central/rev/2bd430740c37
Author: Yuren Ju <yurenju@gmail.com>
Desc: Revert "Bug 957932 - Add coverage checkbox for test-agent web interface"

This reverts commit 9270745f79b2c2195a13cb24902cb402b08ced06.
Bumping manifests a=b2g-bump