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

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https://hg.mozilla.org/integration/gaia-2_0/rev/58d4a257d2c6
Author: Ryan VanderMeulen <ryanvm@gmail.com>
Desc: Merge pull request #24954 from eliperelman/bug-1079700-v2.0

Bug 1079700 - Correcting errors in performance testing

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https://hg.mozilla.org/integration/gaia-2_0/rev/70a0847fadf1
Author: Eli Perelman <eli@eliperelman.com>
Desc: Bug 1079700 - Correcting errors in performance testing
Bumping manifests a=b2g-bump