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

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https://hg.mozilla.org/integration/gaia-central/rev/d6b49ba6226f
Author: Jose Antonio Olivera Ortega <josea.olivera@gmail.com>
Desc: Merge pull request #15549 from jaoo/959986

Bug 959986 - [DSDS] When one SIM is active, still user can access Call Settings of another SIM card. r=arthurcc

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https://hg.mozilla.org/integration/gaia-central/rev/8f9f9129bf60
Author: Jose Antonio Olivera Ortega <josea.olivera@gmail.com>
Desc: Bug 959986 - [DSDS] When one SIM is active, still user can access Call Settings of another SIM card.
Bumping manifests a=b2g-bump