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

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https://hg.mozilla.org/integration/gaia-central/rev/a384d0c712fc
Author: Greg Weng <snowmantw@gmail.com>
Desc: Merge pull request #14683 from snowmantw/issue945601

Bug 945601 - [LockScreen] The acceleration mode of LockScreen should be more smooth

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https://hg.mozilla.org/integration/gaia-central/rev/5068ccf8638f
Author: Greg Weng (snowmantw) <gweng@mozilla.com>
Desc: Bug 945601 - [LockScreen] The acceleration mode of LockScreen should be more smooth