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

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https://hg.mozilla.org/integration/gaia-central/rev/0f6e4dcd16e1
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #13526 from hfiguiere/bug915158-2

Bug 915158 - Allow setting a marionette runner host at runtime.

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https://hg.mozilla.org/integration/gaia-central/rev/46ac64535f24
Author: Hubert Figuière <hub@figuiere.net>
Desc: Bug 915158 - Allow setting a marionette runner host at runtime.