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

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https://hg.mozilla.org/integration/gaia-1_4/rev/71c1d96a65de
Author: Fabrice Desré <fabrice@desre.org>
Desc: Merge pull request #18564 from chuck-lee/bug-997791_1.3t

Bug 997791 - Only set wifi.enabled when it is changed. r=arthurcc a=1.3T
Bumping manifests a=b2g-bump