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

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https://hg.mozilla.org/integration/gaia-1_3/rev/feecd39f33ef
Author: crdlc <crdlc@tid.es>
Desc: Bug 975834 - homescreen bookmarks do not work for URLs ending in a file
Bumping manifests a=b2g-bump