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

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https://hg.mozilla.org/integration/gaia-central/rev/c180e2b698fc
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #16397 from alivedise/bugzilla/973828/resume-app-on-system-message

Bug 973828 - Resume the app when a system message access a suspending ap...r=etienne

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https://hg.mozilla.org/integration/gaia-central/rev/9937676eb401
Author: Alive Kuo <alegnadise@gmail.com>
Desc: Bug 973828 - Resume the app when a system message access a suspending app
Bumping manifests a=b2g-bump