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

========

https://hg.mozilla.org/integration/gaia-central/rev/40dbaf70ab74
Author: Florin Strugariu <florin.strugariu@softvision.ro>
Desc: Merge pull request #26716 from davehunt/bug1074117-persona

Bug 1074117 - Use expected conditions and optimise element lookups in persona app object

========

https://hg.mozilla.org/integration/gaia-central/rev/491502ccf0a3
Author: Dave Hunt <dave.hunt@gmail.com>
Desc: Bug 1074117 - Use expected conditions and optimise element lookups in persona app object. r=fstrugariu
Bumping manifests a=b2g-bump