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

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https://hg.mozilla.org/integration/gaia-central/rev/92bddc1a99aa
Author: Jim Porter <jporter@mozilla.com>
Desc: Merge pull request #21236 from jimporter/ringtones-mp3

Bug 1032702 - Cannot select preloaded MP3 as ringtone

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https://hg.mozilla.org/integration/gaia-central/rev/c05b4c2f1193
Author: Jim Porter <jporter@mozilla.com>
Desc: Bug 1032702 - Cannot select preloaded MP3 as ringtone
Bumping manifests a=b2g-bump