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

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https://hg.mozilla.org/integration/gaia-central/rev/53b04508404f
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #19381 from KevinGrandon/bug_1012578_shared_grid_logic

Bug 1012578 - Abstract grid rendering logic for use in multiple apps

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https://hg.mozilla.org/integration/gaia-central/rev/39390ad2ce90
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1012578 - Abstract grid rendering logic for use in multiple apps r=crdlc, armin

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https://hg.mozilla.org/integration/gaia-central/rev/3afd86611b00
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #19425 from KevinGrandon/bug_1010553_gaia_switch_rename

Bug 1010553 - GaiaSwitch follow-up, rename to follow platform standards

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https://hg.mozilla.org/integration/gaia-central/rev/42126e006bb5
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1010553 - GaiaSwitch follow-up, rename to follow platform standards r=me
Bumping manifests a=b2g-bump