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

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https://hg.mozilla.org/integration/gaia-central/rev/88fb961879f4
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #13466 from mcjimenez/bug933752

Bug 933752 - Creates a new objectstore without doing a proper db migration

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https://hg.mozilla.org/integration/gaia-central/rev/2125028ed75b
Author: Carmen Jimenez Cabezas <cjc@tid.es>
Desc: Bug 933752 - Creates a new objectstore without doing a proper db migration

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https://hg.mozilla.org/integration/gaia-central/rev/2e0c8f575d60
Author: Arthur Chen <crh0716@gmail.com>
Desc: Merge pull request #13613 from crh0716/930223

Bug 930223 - Use os version instead of build ID r=evelyn

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https://hg.mozilla.org/integration/gaia-central/rev/6641c6e38b0a
Author: Arthur Chen <crh0716@gmail.com>
Desc: Bug 930223 - Use os version instead of build ID