Bumping gaia.json for 1 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/d7f12b3592ed
Author: BavarianTomcat <tomcat@mozilla.com>
Desc: Revert "Bug 969215 - Execute |make| should only build specific apps we modified" for causing bug 1087967

This reverts commit 5c3aa46c1353b99dcdc160543a6490df0701e05a.
Bumping manifests a=b2g-bump