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

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https://hg.mozilla.org/integration/gaia-central/rev/ef8101e0a563
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Bug 1071988 - Include date_time_helper.js"

This reverts commit e86143f5a64f68bc182be48836d7ff0e397e8b3f.
Bumping manifests a=b2g-bump