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

========

https://hg.mozilla.org/integration/gaia-central/rev/7e74cd326388
Author: Mason Chang <mason@masonchang.com>
Desc: Merge pull request #15419 from changm/bug958318

bug 958318 - Optimize Settings App to find homescreen counts r=arthurcc

========

https://hg.mozilla.org/integration/gaia-central/rev/b5140d288365
Author: Mason Chang <mchang@mozilla.com>
Desc: bug 958318 - Optimize Settings App to find homescreen counts r=arthurcc

========

https://hg.mozilla.org/integration/gaia-central/rev/ac405438ecc2
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #15426 from KevinGrandon/bug_952098_revert_places

Revert "Bug 952098 - Add places as a rocketbar provider. r=kgrandon"

========

https://hg.mozilla.org/integration/gaia-central/rev/184839b5c5f3
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Revert "Bug 952098 - Add places as a rocketbar provider. r=kgrandon"

This reverts commit ff30172aa6f374c4c4cc3450dd3bb0dcff6d30d5.