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

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https://hg.mozilla.org/integration/gaia-central/rev/b64e4dad1ff3
Author: ochameau <poirot.alex@gmail.com>
Desc: Merge pull request #20227 from ochameau/branding

Bug 1022633 - Fix branding path in DEBUG=1 mode. r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/7f5891d0b1ac
Author: Alexandre Poirot <poirot.alex@gmail.com>
Desc: Bug 1022633 - Fix branding path in DEBUG=1 mode. r=yurenju

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https://hg.mozilla.org/integration/gaia-central/rev/db8b77526226
Author: James Lal <james@lightsofapollo.com>
Desc: Merge pull request #20380 from lightsofapollo/hosted-app-icon-test

Bug 1022094 - Add test to cover appcache installed download case a=test-...

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https://hg.mozilla.org/integration/gaia-central/rev/0a548d50d151
Author: James Lal <james@lightsofapollo.com>
Desc: Bug 1022094 - Add test to cover appcache installed download case a=test-only
Bumping manifests a=b2g-bump