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

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https://hg.mozilla.org/integration/gaia-central/rev/1b846519bdcc
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #20486 from pivanov/bug-1021380

Bug 1021380 - [flame][contacts] icons when contact list is empty seem fuzzy

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https://hg.mozilla.org/integration/gaia-central/rev/6f82d3e06b94
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 1021380 - [flame][contacts] icons when contact list is empty seem fuzzy

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https://hg.mozilla.org/integration/gaia-central/rev/59cc5bce8bba
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Merge pull request #20271 from pivanov/bug-1023117

Bug 1023117

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https://hg.mozilla.org/integration/gaia-central/rev/88f2a69b91c4
Author: Pavel Ivanov <pivanov@mozilla.com>
Desc: Bug 1023117 - [Flame][Camera]Missing images for Camera
Bumping manifests a=b2g-bump