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

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https://hg.mozilla.org/integration/gaia-central/rev/9e971d42c915
Author: Eli Perelman <eli@eliperelman.com>
Desc: Merge pull request #26887 from eliperelman/bug-1088118

Bug 1088118 - Adding User Timing markers to applications

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https://hg.mozilla.org/integration/gaia-central/rev/319db3c787ff
Author: Eli Perelman <eli@eliperelman.com>
Desc: Bug 1088118 - Adding User Timing markers to applications
Bumping manifests a=b2g-bump