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

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https://hg.mozilla.org/integration/gaia-central/rev/5a0a8d0cb665
Author: Sam Joch <samuel@guiora.com>
Desc: Merge pull request #12338 from pivanov/bug-917857

Bug 917857 - [System] Use Full Line Highlights in value selectors r=samjoch

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https://hg.mozilla.org/integration/gaia-central/rev/cbcc0cc01152
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 917857 - [System] Use Full Line Highlights in value selectors