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

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https://hg.mozilla.org/integration/gaia-central/rev/de0afaa8f770
Author: Manuel Casas Barrado <mancas.91@gmail.com>
Desc: Bug 1040981 - [B2G][Browser] While in landscape mode the 'Default search engine' drop down is cut off r=kgrandon
Bumping manifests a=b2g-bump