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

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https://hg.mozilla.org/integration/gaia-central/rev/27556b3448ae
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #13622 from jmcanterafonseca/fix_regression_ds_api

Bug 937361 - [B2G][Contacts] Facebook contacts imported do not appear in...

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https://hg.mozilla.org/integration/gaia-central/rev/8354fe4d3aea
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Bug 937361 - [B2G][Contacts] Facebook contacts imported do not appear in Contacts