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

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https://hg.mozilla.org/integration/gaia-central/rev/f6d7be129a7d
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #12730 from gtorodelvalle/contacts-bug-924385-no-duplicates-overlay

Bug 924385 - [Contacts] The closing of the "No duplicates" overlay leave s the Contacts app unusable (no events dispathed).

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https://hg.mozilla.org/integration/gaia-central/rev/edddd40ef213
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Bug 924385 - [Contacts] The closing of the "No duplicates" overlay leaves the Contacts app unusable (no events dispathed).