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

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https://hg.mozilla.org/integration/gaia-central/rev/8ad87e1aa6aa
Author: punamdahiya <punamdahiya@yahoo.com>
Desc: Merge pull request #15167 from punamdahiya/Bug950184

Bug950184 - Fix of dotted line in header bar r=arnau

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https://hg.mozilla.org/integration/gaia-central/rev/2c6c2c03aefd
Author: Punam Dahiya <punamdahiya@yahoo.com>
Desc: Bug950184 - Fix of dotted line in header bar r=arnau