Bumping gaia.json for 3 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/1189bd58e188
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #13205 from lightsofapollo/v1.2-gaia-ui-tests-travis

V1.2 gaia ui tests travis

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https://hg.mozilla.org/integration/gaia-1_2/rev/f82e8b6f3f6d
Author: Ben Kelly <ben@wanderview.com>
Desc: Bug 928631: support sym linked b2g in gaia-ui-test

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https://hg.mozilla.org/integration/gaia-1_2/rev/397196c3d38d
Author: James Lal <james@lightsofapollo.com>
Desc: Bug 916305 - Gaia ui test travis setup