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

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https://hg.mozilla.org/integration/gaia-central/rev/1508861d8a8d
Author: Anthony Ricaud <anthony@ricaud.me>
Desc: Merge pull request #21638 from tamarahills/bugfix/1029721

Gaia fix for placing cdma call waiting call in the call log r=gsvelto

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https://hg.mozilla.org/integration/gaia-central/rev/37d284579fa0
Author: Tamara Hills <thills@mozilla.com>
Desc: Bug 1029721 - CDMA call waiting call is not logged in call history
Bumping manifests a=b2g-bump