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

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https://hg.mozilla.org/integration/gaia-central/rev/9268056a9744
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Merge pull request #15366 from gtorodelvalle/contacts-bug-931711-contact-id-down

Bug 931711 - mozContact constructor creates unconsistent objects with the 'undefined' string as 'id'

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https://hg.mozilla.org/integration/gaia-central/rev/0cfa0f927578
Author: Germán Toro del Valle <gtorodelvalle@gmail.com>
Desc: Bug 931711 - mozContact constructor creates unconsistent objects with the 'undefined' string as 'id'
Bumping manifests a=b2g-bump