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

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https://hg.mozilla.org/integration/gaia-central/rev/b75625390b4d
Author: Alive.Kuo <alegnadise@gmail.com>
Desc: Merge pull request #13230 from fbukevin/issue929377

Bug 929377 - [LockScreen][UtilityTray] Sleep the phone when UtilityTray shows would make it overlay on lockscreen, r=alive

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https://hg.mozilla.org/integration/gaia-central/rev/eca939e4d1a3
Author: Veck Hsiao <fbukevin@gmail.com>
Desc: Bug 929377 - [LockScreen][UtilityTray] Sleep the phone when UtilityTray shows would make it overlay on lockscreen