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

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https://hg.mozilla.org/integration/gaia-central/rev/de3d3ac16def
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #20785 from AndreiH/bug_1028045

Bug 1028045 - [v2.1] Unxfail [test_ftu_skip_tour.py]

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https://hg.mozilla.org/integration/gaia-central/rev/b315a3bea335
Author: Andrei Hutusoru <andreihutusoru@P5069.(none)>
Desc: Bug 1028045 - [v2.1] Unxfail [test_ftu_skip_tour.py]
Bumping manifests a=b2g-bump