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

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https://hg.mozilla.org/integration/gaia-central/rev/f951aca0eccb
Author: George <georgeiscoming@gmail.com>
Desc: Merge pull request #20478 from cctuan/1024882

Bug 1024882 - [Window Management] Copy-paste gaia changes since gecko api update

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https://hg.mozilla.org/integration/gaia-central/rev/e61af1b043e5
Author: cctuan <georgeiscoming@gmail.com>
Desc: Bug 1024882 - [Window Management] Copy-paste gaia changes since gecko api update
Bumping manifests a=b2g-bump