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

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https://hg.mozilla.org/integration/gaia-central/rev/d29cf66ccf55
Author: punamdahiya <punamdahiya@yahoo.com>
Desc: Merge pull request #19778 from punamdahiya/Bug1015448

Bug1015448 - [Wallpaper] - Fix wall paper file types and sizes r=patryk

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https://hg.mozilla.org/integration/gaia-central/rev/a9f0486ed1ab
Author: Punam Dahiya <punamdahiya@yahoo.com>
Desc: Bug1015448 - [Wallpaper] - Fix wall paper file types and sizes r=patryk
Bumping manifests a=b2g-bump