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

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https://hg.mozilla.org/integration/gaia-central/rev/4a2a66008181
Author: RickyChien <ricky060709@gmail.com>
Desc: Merge pull request #24159 from RickyChien/bug-1050709

Bug 1050709 - execute preference.js in pre-app.js r=@yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/2340bc7c3179
Author: Ricky Chien <ricky060709@gmail.com>
Desc: Bug 1050709 - execute preference.js in pre-app.js
Bumping manifests a=b2g-bump