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

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https://hg.mozilla.org/integration/gaia-central/rev/457d29d40f88
Author: Florin Strugariu <bebef_1987@yahoo.com>
Desc: Merge pull request #17975 from AndreiH/bug_992162

Bug 992162 - [master] Fix test_lockscreen_unlock_to_camera_with_passcode...

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https://hg.mozilla.org/integration/gaia-central/rev/a1c26ad93f62
Author: Andrei Hutusoru <andreihutusoru@P5069.(none)>
Desc: Bug 992162 - [master] Fix test_lockscreen_unlock_to_camera_with_passcode.TestCameraUnlockWithPasscode
Bumping manifests a=b2g-bump