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

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https://hg.mozilla.org/integration/gaia-central/rev/ebbb5a8bc0b8
Author: Francisco Jordano <fjordano@mozilla.com>
Desc: Bug 1064256 - [Contacts] "TypeError: iceGroup is null"

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https://hg.mozilla.org/integration/gaia-central/rev/37fc0bed3d28
Author: Ryan VanderMeulen <rvandermeulen@mozilla.com>
Desc: Revert "Bug 1064256 - [Contacts] "TypeError: iceGroup is null""

This reverts commit 186a163b0304dccc0ffc1918ae70c16c966291a0.
Bumping manifests a=b2g-bump