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

========

https://hg.mozilla.org/integration/gaia-central/rev/5202dd7afec0
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #21858 from KevinGrandon/bug_1037256_icon_installation_location_2

Bug 1037256 - [Vertical Homescreen] Newly installed apps are placed into a new group if homescreen has been killed

========

https://hg.mozilla.org/integration/gaia-central/rev/38b63f77007a
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1037256 - [Vertical Homescreen] Newly installed apps are placed into a new group if homescreen has been killed r=crdlc

========

https://hg.mozilla.org/integration/gaia-central/rev/c76ff842789c
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #21852 from crdlc/bug-1039961

Bug 1039961 - [B2G][OTA] The migration process is performed twice if the...

========

https://hg.mozilla.org/integration/gaia-central/rev/72e5bf03fec9
Author: crdlc <crdlc@tid.es>
Desc: Bug 1039961 - [B2G][OTA] The migration process is performed twice if the user enters in the tutorial
Bumping manifests a=b2g-bump