Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

========

https://hg.mozilla.org/integration/gaia-central/rev/63f0db031313
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #16948 from crdlc/bug-drag-tests

Bug 946728 - DragDrop unit tests fail

========

https://hg.mozilla.org/integration/gaia-central/rev/4f7e11c9edb0
Author: crdlc <crdlc@tid.es>
Desc: Bug 946728 - DragDrop unit tests fail

========

https://hg.mozilla.org/integration/gaia-central/rev/67b9742a5f29
Author: Cristian Rodriguez <crdlc@tid.es>
Desc: Merge pull request #16944 from crdlc/bug-980237

Bug 980237 - The bookmarks edition screen closes automatically

========

https://hg.mozilla.org/integration/gaia-central/rev/d5122312883c
Author: crdlc <crdlc@tid.es>
Desc: Bug 980237 - The bookmarks edition screen closes automatically
Bumping manifests a=b2g-bump