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

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https://hg.mozilla.org/integration/gaia-central/rev/7e375ae2d3b9
Author: Douglas Sherk <github@sherk.me>
Desc: Merge pull request #19037 from DouglasSherk/1007212-sms-only

Bug 1007212 - [Messages] Remove .only tag left in thread_list_ui_test.js r=julienw

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https://hg.mozilla.org/integration/gaia-central/rev/df098996d3b6
Author: DouglasSherk <github@sherk.me>
Desc: Bug 1007212 - [Messages] Remove .only tag left in thread_list_ui_test.js. r=julienw
Bumping manifests a=b2g-bump