Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/6f92062fa8e1
Author: John Hu <johu@mozilla.com>
Desc: Merge pull request #19361 from huchengtw-moz/Stingray/Bug_1002343-save-load-result

Bug 1002343 - [Stingray] persistent module of widget editor, r=lchang, r=garychen

========

https://hg.mozilla.org/integration/gaia-central/rev/ac5c39dc8821
Author: John Hu <johu@mozilla.com>
Desc: Bug 1002343 - [Stingray] persistent module of widget editor

========

https://hg.mozilla.org/integration/gaia-central/rev/ab585fd6a223
Author: Yuren Ju <yurenju@gmail.com>
Desc: Merge pull request #19371 from yurenju/json

Bug 1012596 - Dump more information if get error from |utils.getJSON()| r=@timdream

========

https://hg.mozilla.org/integration/gaia-central/rev/c28b5260c4a1
Author: Yuren Ju <yurenju@gmail.com>
Desc: Bug 1012596 - Dump more information if get error from |utils.getJSON()|
Bumping manifests a=b2g-bump