Bumping gaia.json for 6 gaia revision(s) a=gaia-bump

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https://hg.mozilla.org/integration/gaia-central/rev/a7f08415f2dc
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Merge pull request #22394 from allstarschh/Bug1046554

Bug1046554 - B2G NFC: pass NFCPeerEvent in onpeerready. r=johu, dkuo, punam, francisco, daleharvey.

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https://hg.mozilla.org/integration/gaia-central/rev/12b7fb3d3e03
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Bug 1046554 - Part 5: Contacts app change.

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https://hg.mozilla.org/integration/gaia-central/rev/4879e5a9f1b1
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Bug 1046554 - Part 4: Browser app change

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https://hg.mozilla.org/integration/gaia-central/rev/634ebfbade08
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Bug 1046554 - Part 3: Music app change

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https://hg.mozilla.org/integration/gaia-central/rev/15a0a4b70a6a
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Bug 1046554 - Part 2: Video app change.

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https://hg.mozilla.org/integration/gaia-central/rev/431cdd4e81ab
Author: Yoshi Huang <allstars.chh@mozilla.com>
Desc: Bug 1046554 - Part 1: Gallery change.
Bumping manifests a=b2g-bump