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

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https://hg.mozilla.org/integration/gaia-central/rev/58fe6b7c3ae4
Author: James Burke <jrburke@gmail.com>
Desc: Merge pull request #19492 from jrburke/bug1010867-email-slow-down-there-buddy

Bug 1010867 - [OPENC_1.3][email/UI] Message notification handling is pushing message_reader onto the stack twice r=asuth

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https://hg.mozilla.org/integration/gaia-central/rev/ebe506ff8c45
Author: jrburke <jrburke@gmail.com>
Desc: Bug 1010867 - [OPENC_1.3][email/UI] Message notification handling is pushing message_reader onto the stack twice
Bumping manifests a=b2g-bump