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

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https://hg.mozilla.org/integration/gaia-central/rev/d307a5bd146f
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1009269 - Disable intermittent failing test, Vertical - Bookmark Bookmarking appends to last group
Bumping manifests a=b2g-bump