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

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https://hg.mozilla.org/integration/gaia-central/rev/e9cacbec68bd
Author: gitmai <mri@tid.es>
Desc: Merge pull request #19819 from gitmai/bug-1017581-error-settings

Bug 1017581 -Usage app shows nothing post upgrade
r=salva

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https://hg.mozilla.org/integration/gaia-central/rev/172fa41dfbd8
Author: mai <mri@tid.es>
Desc: Bug 1017581 -Usage app shows nothing post upgrade
Bumping manifests a=b2g-bump