Bumping gaia.json for 1 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/ddbce8d8bd5a
Author: b2gautomation <jonallengriffin@gmail.com>
Desc: Bug 907941 - gaia-ui-tests-pushbot (see bug)
Backed out changeset 679f571996e8 (bug 907585)
Backed out changeset 8b6235d4c2ac (bug 873351)
Backed out changeset 21b97e0e5a10 (bug 907585)
Backed out changeset 0a1f354d13a0 (bug 907585)
Backed out changeset 0b45d07ccdee (bug 907585)
Backed out changeset 89113a5b091e (bug 864485)
Backed out changeset 9bd4fcd6d084 (bug 864485)
Backed out changeset 9a72765987b8 (bug 864485) for mochitest-3 failures on a CLOSED TREE