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

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https://hg.mozilla.org/integration/gaia-central/rev/1265e2a0f500
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Merge pull request #17372 from gtorodelvalle/contacts-bug-982260-intermittent-failure

Bug 982260 - Gaia-integration tests on TBPL fail with: TEST-UNEXPECTED-FAIL | Contacts > Details Merging 15 contacts

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https://hg.mozilla.org/integration/gaia-central/rev/123b19d43034
Author: German Toro del Valle <gtorodelvalle@gmail.com>
Desc: Bug 982260 - Gaia-integration tests on TBPL fail with: TEST-UNEXPECTED-FAIL | Contacts > Details Merging 15 contacts
Bumping manifests a=b2g-bump