Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/180725feea88
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Merge pull request #23287 from qdot/938171-migrate-bookmarks

Bug 938171 - Add app_migrator module include to bootstrap unit test

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https://hg.mozilla.org/integration/gaia-central/rev/92c3d54603fe
Author: Kyle Machulis <kyle@nonpolynomial.com>
Desc: Bug 938171 - Add app_migrator module include to bootstrap unit test
Bumping manifests a=b2g-bump