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

========

https://hg.mozilla.org/integration/gaia-central/rev/310f72876978
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Merge pull request #22185 from dmarcos/bug1039629

Bug 1039629 - [B2G] [Camera] Placeholder warning text is shown when Came...

========

https://hg.mozilla.org/integration/gaia-central/rev/d0ce4589cd57
Author: Diego Marcos <diego.marcos@gmail.com>
Desc: Bug 1039629 - [B2G] [Camera] Placeholder warning text is shown when Camera is launched with low battery
Bumping manifests a=b2g-bump