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

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https://hg.mozilla.org/integration/gaia-2_1/rev/ff3959b72fb3
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1062942 - [Browser Start Page] Visual tweaks to headers r=epang

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https://hg.mozilla.org/integration/gaia-2_1/rev/99f99180b294
Author: Kevin Grandon <kevingrandon@yahoo.com>
Desc: Bug 1061674 - [Rocketbar] SSL icon asset swap r=epang

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https://hg.mozilla.org/integration/gaia-2_1/rev/b2dbe3a7b891
Author: Chris Lord <chrislord.net@gmail.com>
Desc: Bug 1062321 - Fix notification overflow not being scrollable. r=mhenretty

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https://hg.mozilla.org/integration/gaia-2_1/rev/5fe7ce85ec52
Author: Fernando Jiménez <ferjmoreno@gmail.com>
Desc: Bug 1059488 - [MobileID] Country code manual selection dialog seems broken. r=alive
Bumping manifests a=b2g-bump