Bumping gaia.json for 4 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/fc40122e9b26
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Merge pull request #23936 from timdream/keyboard-page-target

Bug 1047837 - Codify the concept of layout v.s. layout page, r=rudyl, r=zac, f=mnjul

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https://hg.mozilla.org/integration/gaia-central/rev/6b2b662acb55
Author: Timothy Guan-tin Chien <timdream@gmail.com>
Desc: Bug 1047837 - Codify the concept of layout and layout page

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https://hg.mozilla.org/integration/gaia-central/rev/b6c6ac43af52
Author: steveck-chung <schung@mozilla.com>
Desc: Merge pull request #23939 from steveck-chung/crop-image-workaround

Bug 1059233 - [SMS] Opening cropped image attachment returned from gallery might cause error, r=azasypkin

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https://hg.mozilla.org/integration/gaia-central/rev/eb1edafada4f
Author: Steve Chung <schung@mozilla.com>
Desc: Bug 1059233 - [SMS] Opening cropped image attachment returned from gallery might cause error, r=azasypkin
Bumping manifests a=b2g-bump