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

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https://hg.mozilla.org/integration/gaia-central/rev/02019aed972b
Author: Ghislain 'Aus' Lacroix <aus@noiseport.org>
Desc: Merge pull request #12927 from nullaus/bug918143-group-notifications

bug 918143

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https://hg.mozilla.org/integration/gaia-central/rev/1040d7160b72
Author: Ghislain 'Aus' Lacroix <aus@mozilla.com>
Desc: bug 918143
-check for existing notification with same tag before inserting a new notification on lockscreen.
-add marionette tests for lockscreen notifications.

r=qDot