Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/19e191647a06
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #23516 from KevinGrandon/bug_1037716_reenable_manage_test

Bug 1037716 - Re-enable apps/ringtones/test/marionette/manage_test.js

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https://hg.mozilla.org/integration/gaia-central/rev/fbd69c6d3f6b
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1037716 - Re-enable apps/ringtones/test/marionette/manage_test.js r=kgrandon

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https://hg.mozilla.org/integration/gaia-central/rev/4596b0c6a57f
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #23075 from crh0716/1032631

Bug 1032631 - Add EU roaming manager r=eragonj, alive

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https://hg.mozilla.org/integration/gaia-central/rev/be1424034efa
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 1032631 - Add EU roaming manager
Bumping manifests a=b2g-bump