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

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https://hg.mozilla.org/integration/gaia-central/rev/d51f271a16ba
Author: Johan Lorenzo <jlorenzo@mozilla.com>
Desc: Bug 1099041 - Add the manifest file that sets the default values as a dependency to the others. r=dhunt
Bumping manifests a=b2g-bump