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

========

https://hg.mozilla.org/integration/gaia-central/rev/e51e4db9e6cd
Author: Sergi Mansilla <sergi.mansilla@gmail.com>
Desc: Merge pull request #23850 from sergi/BUG_1061662

Bug 1061662 - [Contacts] Wrong images on contacts when building with GAIA_DEV_PIXELS_PER_PX=1.5 r=francisco

========

https://hg.mozilla.org/integration/gaia-central/rev/0586b53f60e0
Author: Sergi Mansilla <sergi.mansilla@gmail.com>
Desc: Bug 1061662 - [Contacts] Wrong images on contacts when building with GAIA_DEV_PIXELS_PER_PX=1.5
Bumping manifests a=b2g-bump