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

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https://hg.mozilla.org/integration/gaia-central/rev/7aa503060000
Author: John Hu <johu@mozilla.com>
Desc: Merge pull request #12189 from huchengtw-moz/camera/Bug_915994_show_preview_when_preview_is_not_big_enough

Bug 915994 - [Camera][REG] reset of media frame still trying to show pre..., r=djf

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https://hg.mozilla.org/integration/gaia-central/rev/43b6068f4806
Author: John Hu <johu@mozilla.com>
Desc: Bug 915994 - [Camera][REG] reset of media frame still trying to show preview image when it is not big enough