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

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https://hg.mozilla.org/integration/gaia-central/rev/d818ea3ebb2a
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Merge pull request #15891 from davidflanagan/revert959049

Revert "Merge pull request #15702 from davidflanagan/bug959049"

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https://hg.mozilla.org/integration/gaia-central/rev/118237d38edb
Author: David Flanagan <dflanagan@mozilla.com>
Desc: Revert "Merge pull request #15702 from davidflanagan/bug959049"

This reverts commit cfeb5bf7e7665e4be412d1f774bd46fadeff3c93, reversing
changes made to a9a4e7bbcf55d1bd0a0d441f7dcc6271cc2dc6b1.
Bumping manifests a=b2g-bump