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

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https://hg.mozilla.org/integration/gaia-central/rev/b4a339e0130b
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #21771 from zacc/bug_1020166

Bug 1020166 - test_settings_device_info.py - Only check the first IMEI i...

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https://hg.mozilla.org/integration/gaia-central/rev/8a5f53a1db03
Author: Zac <zcampbell@mozilla.com>
Desc: Bug 1020166 - test_settings_device_info.py - Only check the first IMEI in Settings app
Bumping manifests a=b2g-bump