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

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https://hg.mozilla.org/integration/gaia-central/rev/cd4593d3318c
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #21182 from viorelaioia/1028192

Bug 1028192 - Disable ActiveSync tests

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https://hg.mozilla.org/integration/gaia-central/rev/7f9e7c9ccab8
Author: Viorela Ioia <viorelaioia@gmail.com>
Desc: Bug 1028192 - Disable ActiveSync tests
Bumping manifests a=b2g-bump