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

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https://hg.mozilla.org/integration/gaia-central/rev/17a7e26d46c0
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #13852 from bgirard/HomescrenBackground

Bug 917416 - Move wallpaper into the Homescreen app. r=gal

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https://hg.mozilla.org/integration/gaia-central/rev/fd764fab84f1
Author: Benoit Girard <b56girard@gmail.com>
Desc: Bug 917416 - Move wallpaper into the Homescreen app. r=gal

b2g/config/gaia.json

@@ -1,4 +1,4 @@
 {
-    "revision": "60bf20cba4daf5f05870826c1f2735b0b3ea161a", 
+    "revision": "17a7e26d46c0a3230f4cb8416b56e7ad28d3296c", 
     "repo_path": "/integration/gaia-central"
 }