Bumping gaia.json for 2 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/c4b86becad2b
Author: gasolin <gasolin@gmail.com>
Desc: Merge pull request #25791 from gasolin/issue-1089511-3

Bug 1089511 - refactor system/js/bluetooth to future compatible format, r=alive&Ian

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https://hg.mozilla.org/integration/gaia-central/rev/1a92945817f4
Author: gasolin <gasolin@gmail.com>
Desc: Bug 1089511 - refactor system/js/bluetooth to future compatible format
Bumping manifests a=b2g-bump