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

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https://hg.mozilla.org/integration/gaia-central/rev/c144b6204fb2
Author: Carsten Book <tomcat@mozilla.com>
Desc: Merge pull request #25269 from mancas/bug1081243

Bug 1081243 - [Downloads] A recently download file can not be open. r=ejchen

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https://hg.mozilla.org/integration/gaia-central/rev/531e713c3a3d
Author: Manuel Casas Barrado <manuel.casasbarrado@telefonica.com>
Desc: Bug 1081243 - [Downloads] A recently download file can not be open
Bumping manifests a=b2g-bump