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

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https://hg.mozilla.org/integration/gaia-1_3/rev/91962ccd3afb
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #18281 from chirarobert/v1.3_airplane

Bug 995964 - [v1.3] Fix for test_settings_airplane_mode.py

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https://hg.mozilla.org/integration/gaia-1_3/rev/70adf1785594
Author: chirarobert <robert.chira@softvision.ro>
Desc: Bug 995964 - [v1.3] Fix for test_settings_airplane_mode.py
Bumping manifests a=b2g-bump
Bumping manifests a=b2g-bump
Bug 966843 - Fix intermittent browser_615394-SSWindowState_events.js hangs. r=smacleod, a=test-only
Bug 892990 - Cap waiting time for wait-for-composite in WebGL reftests. r=bjacob, a=test-only
Bug 993546 - Refactor malloc-wrapping memory reporter implementations. r=njn, a=1.3+
Bug 993546 - Add missing comma. a=bustage
Bug 993546 - Fix uplift rebasing error. a=bustage
Bug 980679 - Filter redundant scroll offset updates by scroll generation value. r=botond,tn a=bajaj
Merge b2g28 to v1.3t. a=merge