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

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https://hg.mozilla.org/integration/gaia-central/rev/1605437479dc
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Merge pull request #23291 from mozilla-b2g/revert-23287-938171-migrate-bookmarks

Revert "Bug 938171 - Add app_migrator module include to bootstrap unit t...

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https://hg.mozilla.org/integration/gaia-central/rev/619bbb2fe05c
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Revert "Bug 938171 - Add app_migrator module include to bootstrap unit test"

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https://hg.mozilla.org/integration/gaia-central/rev/86f2efc727d2
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Merge pull request #23290 from mozilla-b2g/revert-23119-938171-migrate-bookmarks

Revert "Bug 938171 - Browser Bookmark Migration to Homescreen in Gaia"

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https://hg.mozilla.org/integration/gaia-central/rev/1033dfbf1461
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Revert "Bug 938171 - Browser Bookmark Migration to Homescreen in Gaia"
Bumping manifests a=b2g-bump