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

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https://hg.mozilla.org/integration/gaia-central/rev/d47d0a9beca3
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #16452 from zacc/bug962795

Bug 962795 - Re-enable python e.me tests

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https://hg.mozilla.org/integration/gaia-central/rev/b9e32a70f315
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 962795 - Re-enable python e.me tests

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https://hg.mozilla.org/integration/gaia-central/rev/c6807635e6b8
Author: Zac <zcampbell@mozilla.com>
Desc: Merge pull request #16420 from zacc/bug_974048

Bug 974048 - Refine waits when connecting to a WiFi network

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https://hg.mozilla.org/integration/gaia-central/rev/0b2cd21bc3f8
Author: Zac Campbell <zcampbell@mozilla.com>
Desc: Bug 974048 - Refine waits when connecting to a WiFi network
Bumping manifests a=b2g-bump