Bumping gaia.json for 2 gaia-central revision(s)

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https://hg.mozilla.org/integration/gaia-central/rev/afc8c02bc448
Author: Francisco Jordano <arcturus@ardeenelinfierno.com>
Desc: Merge pull request #11638 from arcturus/bug-887673

Bug 887673 - [User Story] Export of contact to USIM

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https://hg.mozilla.org/integration/gaia-central/rev/2fc77fe46af2
Author: Francisco Jordano <arcturus@ardeenelinfierno.com>
Desc: Bug 887673 - [User Story] Export of contact to USIM