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

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https://hg.mozilla.org/integration/gaia-central/rev/6270abbfd386
Author: Zibi Braniecki <zbigniew.braniecki@gmail.com>
Desc: Merge pull request #25469 from zbraniecki/1087855-syntax-error-in-fxam-errors-test

Bug 1087855 - Fix fxam_errors_test. r=ferjmoreno

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https://hg.mozilla.org/integration/gaia-central/rev/0fb2c1bb2864
Author: Zbigniew Braniecki <gandalf@mozilla.com>
Desc: Bug 1087855 - Fix fxam_errors_test
Bumping manifests a=b2g-bump