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

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https://hg.mozilla.org/integration/gaia-central/rev/c6aeaa41977d
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #14750 from jmcanterafonseca/fix_export_alpha_scroll

Bug 951107 - alpha scroll in export contacts screen is broken

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https://hg.mozilla.org/integration/gaia-central/rev/89986d9dfd30
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 951107 - alpha scroll in export contacts screen is broken