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

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https://hg.mozilla.org/integration/gaia-central/rev/184a0e992fa2
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Merge pull request #15917 from etiennesegonzac/bug-962649-nice-to-the-event-loop

Bug 962649 - Be nicer to the event loop during edge gestures. r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/cf528744acbb
Author: Etienne Segonzac <etienne@segonzac.info>
Desc: Bug 962649 - Be nicer to the event loop during edge gestures.

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https://hg.mozilla.org/integration/gaia-central/rev/780b8377bc65
Author: Arnau <arnau@arnaumarch.com>
Desc: Merge pull request #16395 from nucliweb/840918-Cost-Control

Solved overflow on progress bar when minimum values

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https://hg.mozilla.org/integration/gaia-central/rev/2feb5e0f8aa6
Author: Joan Leon <joan.leon@gmail.com>
Desc: Solved overflow on progress bar when minimum values

Add rule for fix it
Bumping manifests a=b2g-bump