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

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https://hg.mozilla.org/integration/gaia-central/rev/91e27e3c94f7
Author: Eitan Isaacson <eitan@monotonous.org>
Desc: Merge pull request #17548 from eeejay/bug-987384

Bug 987384 - [Clock] Add accessibility to analog clock. r=mcav

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https://hg.mozilla.org/integration/gaia-central/rev/796c546613d5
Author: Eitan Isaacson <eitan@monotonous.org>
Desc: Bug 987384 - [Clock] Add accessibility to analog clock.

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https://hg.mozilla.org/integration/gaia-central/rev/a23d36ab5993
Author: Eitan Isaacson <eitan@monotonous.org>
Desc: Merge pull request #17546 from eeejay/bug-987382

Bug 987382 - [Clock] label icon buttons. r=mcav

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https://hg.mozilla.org/integration/gaia-central/rev/efeb80515c0c
Author: Eitan Isaacson <eitan@monotonous.org>
Desc: Bug 987382 - [Clock] label icon buttons.
Bumping manifests a=b2g-bump