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

========

https://hg.mozilla.org/integration/gaia-1_4/rev/acf44ba90b90
Author: AndreiH <andrei.hutusoru@softvision.ro>
Desc: Merge pull request #19713 from AndreiH/bug_1016850

Bug 1016850

========

https://hg.mozilla.org/integration/gaia-1_4/rev/3f9a61e7daa0
Author: Andrei Hutusoru <andreihutusoru@P5069.(none)>
Desc: Bug 1016850 - Intermittent Gaia UI Test Travis failure: TEST-UNEXPECTED-FAIL | test_homescreen_delete_app
Bumping manifests a=b2g-bump