Bumping gaia.json for 1 gaia-1_2 revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-1_2/rev/dccdbf0190c0
Author: Jose M. Cantera <jmcanterafonseca@gmail.com>
Desc: Merge pull request #12604 from jmcanterafonseca/fix_facebook_messaging

Bug 910112 - [B2G][Contacts]When click message button for facebook a con...(cherry picked from commit d1deec8d52ce46f95cf398b333926e5cbf7ae0b0)