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

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https://hg.mozilla.org/integration/gaia-central/rev/591e51dda968
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #21284 from zacc/bug_1030819

Bug 1030819 - Move plivo requirement into the test's requirements file

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https://hg.mozilla.org/integration/gaia-central/rev/15629ab11cb5
Author: Zac <zcampbell@mozilla.com>
Desc: Bug 1030819 - Move plivo requirement into the test's requirements file

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https://hg.mozilla.org/integration/gaia-central/rev/e9b2368c02f9
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 1033260 - [Messages] Contact suggestion list didn't dismiss when focus on subject and message input field r=julien,azasypkin
Bumping manifests a=b2g-bump