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

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https://hg.mozilla.org/integration/gaia-central/rev/ad1884a1465c
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #25195 from KevinGrandon/bug_1033223_bookmark_test_intermittent

Bug 1033223 - [Vertical homescreen] Intermittent MarionetteJS failure on Travis: 1) Vertical - Bookmark Uninstall removal of bookmark: NoSuchElement: (7) Unable to locate element: gaia-confirm[data-type=remove]

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https://hg.mozilla.org/integration/gaia-central/rev/16f882b6a351
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1033223 - [Vertical homescreen] Intermittent MarionetteJS failure on Travis: 1) Vertical - Bookmark Uninstall removal of bookmark: NoSuchElement: (7) Unable to locate element: gaia-confirm[data-type=remove] r=kgrandon
Bumping manifests a=b2g-bump